July 2003
NWMO BACKGROUND PAPERS
4. SCIENCE AND ENVIRONMENT
4-1 CURRENT STATUS OF BIOSPHERE RESEARCH RELATED TO HIGH-LEVEL
RADIOACTIVE WASTE MANAGEMENT (HLRWM)
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NWMO Background Papers
NWMO has commissioned a series of background papers which present concepts and
contextual information about the state of our knowledge on important topics related to the
management of radioactive waste. The intent of these background papers is to provide input to
defining possible approaches for the long-term management of used nuclear fuel and to
contribute to an informed dialogue with the public and other stakeholders. The papers currently
available are posted on NWMO’s web site. Additional papers may be commissioned.
The topics of the background papers can be classified under the following broad headings:
1. Guiding Concepts – describe key concepts which can help guide an informed dialogue
with the public and other stakeholders on the topic of radioactive waste management.
They include perspectives on risk, security, the precautionary approach, adaptive
management, traditional knowledge and sustainable development.
2. Social and Ethical Dimensions - provide perspectives on the social and ethical
dimensions of radioactive waste management. They include background papers
prepared for roundtable discussions.
3. Health and Safety – provide information on the status of relevant research,
technologies, standards and procedures to reduce radiation and security risk associated
with radioactive waste management.
4. Science and Environment – provide information on the current status of relevant
research on ecosystem processes and environmental management issues. They include
descriptions of the current efforts, as well as the status of research into our
understanding of the biosphere and geosphere.
5. Economic Factors - provide insight into the economic factors and financial
requirements for the long-term management of used nuclear fuel.
6. Technical Methods - provide general descriptions of the three methods for the longterm management of used nuclear fuel as defined in the NFWA, as well as other possible
methods and related system requirements.
7. Institutions and Governance - outline the current relevant legal, administrative and
institutional requirements that may be applicable to the long-term management of spent
nuclear fuel in Canada, including legislation, regulations, guidelines, protocols,
directives, policies and procedures of various jurisdictions.
Disclaimer
This report does not necessarily reflect the views or position of the Nuclear Waste Management
Organization, its directors, officers, employees and agents (the “NWMO”) and unless otherwise
specifically stated, is made available to the public by the NWMO for information only. The
contents of this report reflect the views of the author(s) who are solely responsible for the text
and its conclusions as well as the accuracy of any data used in its creation. The NWMO does
not make any warranty, express or implied, or assume any legal liability or responsibility for the
accuracy, completeness, or usefulness of any information disclosed, or represent that the use of
any information would not infringe privately owned rights. Any reference to a specific
commercial product, process or service by trade name, trademark, manufacturer, or otherwise,
does not constitute or imply its endorsement, recommendation, or preference by NWMO.
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Background Paper on the Current Status of Biosphere
Research Related to High-Level Radioactive Waste
Management (HLRWM)
July 21, 2003
SUMMARY
The biosphere is anywhere organisms live. The biosphere research related to high-level
radioactive waste management (HLRWM) deals entirely with the potential effects of the
various management options that might be considered. Effects in the biosphere on
humans or other biota are the ultimate performance criteria for these HLWRM options, so
related biosphere research is quite important. The biosphere cannot be a barrier to the
spread of contamination, because by definition there are organisms present everywhere in
the biosphere, and any of them could be impacted. Thus the biosphere is the potential
receptor of contamination or other impacts from a HLRWM facility. We must
understand the severity of these impacts and be able to engineer facilities to prevent or
minimize them.
Historically, the emphasis in biosphere research related to nuclear environmental
contamination was on the protection of humans, especially from contamination in
agricultural settings. Since about 1996, there have been rapid developments worldwide
to include predictions of effects on non-human biota. Canada has at times been a leader
in issues related to biosphere aspects of HLRWM, and continues to play a role with
contributions to the scientific literature and involvement in international programs.
The underlying scientific discipline, radioecology, has particular strengths in dealing with
the transport and dispersion of radioactive contaminants in soil, water and air. It borrows
from human health and safety research and is well advanced in the estimation of the
additive effects of multiple radioactive contaminants. Radioecology is now adapting
scientific methods from other ecological disciplines to deal with the multiple organisms
present in natural settings.
Although the biosphere is not usually conceived as a manageable barrier, biosphere
research has additional importance because the public identifies with biosphere issues.
This aspect is becoming increasingly more important as the HLWRM programs
worldwide progress and facilities are built.1
1
DISCLAIMER
Unless otherwise specifically stated, the information contained herein is made available to the public by the
Nuclear Waste Management Organization (NWMO) for information only. The NWMO assumes no legal
liability or responsibility for the accuracy, completeness, or usefulness of any information disclosed, or
represents that the use of any information would not infringe privately owned rights. Reference herein to
any specific commercial product, process, service by trade name, trademark, manufacturer, or otherwise,
does not constitute or imply its endorsement, recommendation, or favouring by the NWMO. The views
and opinions of the originators expressed therein do not necessarily state or reflect those of the NWMO.
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TABLE OF CONTENTS
SUMMARY........................................................................................................................ 2
Table of Contents................................................................................................................ 3
Objectives of this Paper ...................................................................................................... 4
INTRODUCTION .............................................................................................................. 4
Previous Research Priorities ........................................................................................... 5
The Biosphere Research Community ............................................................................. 8
Linkage of Research to Assessment ............................................................................. 10
KEY ELEMENTS ............................................................................................................ 10
Biosphere Research and the Risk Assessment Paradigm ............................................. 11
How Biosphere Research is Done................................................................................. 14
The Dualities of Biosphere Research for HLRWM...................................................... 16
Implicit Protection of the Environment ........................................................................ 17
Humans Versus Non-Human Biota .............................................................................. 20
Continued Advances Related to Humans ..................................................................... 24
Glossary ............................................................................................................................ 28
RELATED AREAS .......................................................................................................... 31
Developments in Canada since the Seaborn Report ..................................................... 31
International Developments in the Last Decade ........................................................... 32
Convergence with Research Related to Other Hazardous Wastes................................ 34
How could the impact of HLRWM biosphere research be enhanced?......................... 36
REFERENCES ................................................................................................................. 37
APPENDIX A PAPERS, REPORTS AND CONFERENCE TALKS ON VARIOUS
BIOSPHERE TOPICS FROM THE CANADIAN PROGRAM SINCE 1992 ................ 42
Biosphere Evolution, Onset Of Glaciation And Climate Change................................. 42
Understanding of Underlying Processes....................................................................... 42
Ecological Effects Assessment and Non-Human Biota................................................ 44
Improvements to Risk Assessment Approaches With Respect to the Biosphere ......... 46
Special Risk Assessment Models for 14C, 36Cl and 129I ................................................ 48
Updates to Parameter Values – Iodine, Chlorine, Carbon ............................................ 49
Supporting Research for Biological and Biosphere Connections with the Geosphere. 52
APPENDIX B EXAMPLE OF DOSE ESTIMATES FOR HUMANS VERSUS
NON-HUMAN BIOTA .................................................................................................... 54
Purpose.......................................................................................................................... 54
Description of the Example .......................................................................................... 54
Exposure Assumptions.................................................................................................. 54
Dose Estimates.............................................................................................................. 55
Risk Quotient ................................................................................................................ 55
Conclusion .................................................................................................................... 55
References..................................................................................................................... 55
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OBJECTIVES OF THIS PAPER
The objective of this paper is to describe the current status of biosphere research related
to HLRWM. It will examine biosphere programs in Canada and worldwide, with
particular emphasis on the last decade (1993/2003). Although it will include information
relevant to the three possible management approaches for HLRWM as defined in the
Nuclear Fuel Waste Act, the emphasis will be on potential long-term impacts, which are
somewhat similar for the three approaches.
INTRODUCTION
Biosphere implies any
environment where
something lives, but the
focus is on organisms in
water, soil and air at the
earth’s surface.
Biosphere research2 for high-level radioactive waste
management (HLRWM) focuses on the potential effects of
releases of contamination on living organisms. The
emphasis is on the surface environment (water, soil, air, and
associated organisms) even though micro-organisms can live
deep underground. The emphasis is often on very long-term
impacts (thousands to ten of thousands of years in the
future), because long-term impacts are less easily controlled
than are more immediate ones, and there are existing
regulations and methods to ensure protection for present-day
surface facilities. The long-term perspective means the
biosphere is considered in a rather generic way, because no
one can be sure what the environment will be like that far in
the future. Of particular interest to biosphere research are
the radionuclides found in the high-level waste, their ability
to move in the environment, and their radioactive emissions
(radiation). Fortunately, most biosphere research related to
nuclear waste is relevant to all HLRWM options, and
additionally can very effectively draw from research on other
nuclear facilities such as emissions from power reactors.
For HLRWM, the major
requirement is for
information on how
organisms absorb and are
affected by radionuclides.
Biosphere research is a broad term, and implies the study of
any and all organisms and the environment they need for
sustained survival. For HLRWM, the research emphasis is
on the interactions of biota with radionuclides and radiation.
It is important to note that a great deal of basic information
from the earth and ecological sciences is available to
understand many of the more fundamental biosphere
2
words in bold have specific meanings in this context, and are more fully defined in the GLOSSARY.
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processes. For example, there is information in the literature
on the diet of specific biota such as a muskrat, so that in the
context of HLRWM the biosphere research can emphasize
the uptake of radionuclides and the effects they might cause.
Biosphere research
supports estimation of the
effects against which
HLRWM will be judged.
The role of the biosphere in HLRWM is not as a barrier to
the spread of contamination. The engineered facilities (and
the surrounding rock if it is underground) are the barriers to
contamination. Zero emission of contaminants and radiation
to the environment is the best protection, and is the
engineering objective of HLRWM. However, there is
always the possibility of some escape of contamination to the
environment. As a result, biosphere research has been
conducted to understand the impacts of potential releases.
This is why biosphere research is important to HLRWM: the
ultimate performance criterion for all possible options is the
effect they could have on the biosphere.
Potential releases are more probable over very long time
periods, and some of the wastes will remain hazardous for
thousands of years. Because of this perspective, the role of
biosphere research is not to ‘manage’ the problem of
contamination, but to estimate the potential effects against
which management of other aspects will be judged.
Previous Research Priorities
In the 1970’s, research
was on the survivability of
nuclear war.
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The biosphere research relevant to HLRWM began in the
1970’s, with rather different objectives. With the
proliferation of nuclear weapons, scientists around the world
investigated the impacts of radiation on the environment.
Considerable effort was directed to understanding the
effects on plants, because all life depends on plants as the
ecological primary producers. In one line of research, large
irradiators were set up, usually powerful radiation sources
mounted on poles above natural or agricultural plots. The
effects of this radiation on plants and other biota was
reported, and these data are still some of the best available
(e.g., Sparrow et al. 1971). Canada participated with the
Field Irradiator Gamma (FIG) experiment (Guthrie and
Dugle 1983, photo opposite), which irradiated a plot of
boreal forest in Manitoba, and this was found to be a
particularly sensitive ecological system (Amiro and
Sheppard 1994; Dugle 1986; Sheppard et al. 1982).
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Food chain models were
forefront in the 1980’s, to
calculate dose to humans
as a result of reactor
operations.
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By the 1980’s, biosphere research in the nuclear industry
emphasized the movement and fate of specific radionuclides,
information that was needed to assess the many new nuclear
power developments. Information was acquired and simple
food-chain models were established (Baker 1977; Fletcher
and Dotson 1971; Hoffman et al. 1977; Kaye et al. 1982;
Moore et al. 1979; Napier et al. 1980; Shaeffer and Ethnier
1979) and followed later by Canada’s own standard for
operating reactors (CSA 1987). The radionuclides to be
assessed were from almost every element in the periodic table
(Figure 1). Where necessary, extrapolations were made to
extend the assessment capability to scenarios and
radionuclides for which there were few underlying data (e.g.,
Baes et al. 1984). These extrapolations were thought by some
to have led to decreased funding for biosphere research,
because they gave the impression that the required knowledge
was complete.
Figure 1. An illustration of the interpolation to provide data for
almost every element in the periodic table. Shown are soil
solid/liquid partition coefficients in units of ln(L/kg), from Sheppard
et al. (1992).
Chernobyl and glasnost
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The Chernobyl accident happened in April 1986, and the
contamination consequences became an unfortunate global
opportunity to validate our understanding of biosphere
processes (see photo opposite). Funding levels markedly
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The former ‘Red Forest’,
highly impacted by the
Chernobyl accident.
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increased, and thousands of research papers have been
published on this topic. Shortly after, with the fall of the
Soviet Union, western scientists gained access to several other
catastrophic nuclear accident sites and widely contaminated
regions. Most important to HLRWM are the papers on
biological effects of low-level environmental radiation and
some cases of unexpected radionuclide behaviour. As one
example, there is evidence of developmental instability in
plants (Moller 1998) and field mice (Oleksyk et al. 2003) in
the exclusion zones around Chernobyl. As another example,
it has become evident that in nutrient-poor environments,
contaminants such as cesium (which mimics the essential
nutrient potassium) are very effectively cycled between soils
and plants. As a result, radioactive cesium is not leached out
of the soil as quickly as might otherwise be the case, and
remains an ecological hazard (Desmet et al. 1990).
The future for research
will be for waste
management and
decommissioning of
nuclear facilities.
Recently, and following the bursts of research activity related
to threat of nuclear weapons and Chernobyl, emphasis is
moving toward waste management and decommissioning
issues, and especially toward the potential for impacts on
non-human biota. There is also some research on biological
technologies (plants or micro-organisms) to decontaminate
soil. The level of research activity could increase again if
nuclear power gains momentum under clean energy strategies.
The Canadian biosphere
research has been
thoroughly published in
the scientific literature.
In Canada, research related to disposal of fuel waste began in
the late 1970’s, much of it conducted by the environmental
research scientists at Atomic Energy of Canada Limited
(AECL) Whiteshell Laboratories, with specific inputs from
colleagues at Chalk River Laboratories. This contributed to
an Environmental Impact Statement (an EIS, AECL 1994).
The assessment and research programs were initially funded
entirely by the Federal government. In about 1986 there was
a shift to 50% co-funding from other owners of nuclear fuel
waste (COG, the CANDU Owners Group), and this evolved
so that by the late 1990’s the research was, and continues to
be, fully and directly funded by Ontario Power Generation
(OPG). A Technical Review Group, funded by AECL and
with reviewers drawn from prominent Canadian professional
scientific societies, initially provided scientific review. After
submission of the EIS, the Seaborn Panel was established to
provide independent and multi-stakeholder review, and they
established Scientific Review Groups to critique various
aspects of the EIS, including the biosphere components. In
addition to this formalized review process, the biosphere
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research was extensively published in the open scientific
literature, and over 300 papers and reports received
international peer review in this process.
The Biosphere Research Community
Radioecology is the
discipline that studies
radioactive materials and
radiation effects in the
environment.
number of papers
250
200
150
100
50
0
1995
1997
1999
2001
2003
year
Figure 2. Numbers of papers
published in the Journal of
Environmental Radioactivity
1995 to 2002, as an indication
in the growth of radioecology
(from Sheppard 2003).
There is a long history of
international cooperation
in radioecology.
3
The relevant biosphere research is carried out throughout
the world by scientists in government, university and
industry establishments, with funding from governments
and industry. The university researchers tend to deal with
more theoretical aspects, and orient their research towards
publication in the peer-reviewed scientific literature. Their
research priorities balance the academic need for originality
with the specific requirements of funding agencies. The
other researchers span a broader spectrum, including
excellent theoretical work along with rather pragmatic
modifications from previous knowledge. Their research
may be published in peer-reviewed journals, but there is a
tendency to also, or to only, produce internal institutional
reports. In general, these reports are made publicly
available. The major underlying discipline is called
radioecology, and is the study of radioactive materials and
radiation effects in the environment. The International
Union of Radioecologists (IUR web link3) and the South
Pacific Environmental Radioactivity Association (SPERA
web link) are two prominent related scientific societies.
Several peer-reviewed scientific journals publish relevant
articles, and the Journal of Environmental Radioactivity
(Elsevier Science) has been solely devoted to radioecology
for over 20 years (Figure 2). There are a series of regular
international conferences that are specific to or include
specific sessions on radioecology (e.g., ICOBTE, ECORAD
web links).
The International Atomic Energy Agency (IAEA) provides
some international coordination role, especially in
transferring biosphere information and technology from
well-developed to less-developed nations (e.g., IAEA 1992,
1994). Other international agencies such as the
Organization for Economic Cooperation and Development
(OECD), Food and Agriculture Organization (FAO) and
Nuclear Energy Agency (NEA) include some aspects of
web links to the internet are given in the REFERENCE section.
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radioecology in their mandates. In addition to these
established institutes, various national agencies collaborate
in specific programs to collectively advance the science
(e.g., BIOMOVS: International programme on the
BIOspheric Model Validation Study; BIOMASS: IAEA
project on BIOsphere Modelling and Assessment;
BIOCLIM: on-going European Community project (20002003) 5th Euratom Framework Programme- Modelling
Sequential Biosphere Systems under Climate Change for
Radioactive Waste Disposal; and BIOPROTA: on-going
cooperative project among international waste owners). In
general, radioecology is a relatively strong and stable
discipline in Europe, and it is growing in Asia. There are
several radioecology graduate and post-graduate programs
in radioecology in Europe and Japan. Radioecology has lost
ground as a discipline in North America, and there are
almost no formal training programs. The schematic of the
globe (Figure 3) illustrates the relative effort by country,
based on papers published in the Journal of Environmental
Radioactivity.
Figure 3. Schematic where the size of the country outline is proportional to the numbers
of papers published in the Journal of Environmental Radioactivity, which is an index of
the amount of biosphere research being done for the nuclear industry (not just HLRWM),
from Sheppard (2003).
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Linkage of Research to Assessment
Assessment needs set the
priorities for biosphere
research.
Biosphere research in support of HLRWM in Canada has
been closely linked to meeting the needs of risk assessment.
The program was closely monitored over a decade by an
independent Technical Advisory Committee (TAC 1993),
and this group was especially adamant that the biosphere
research be narrowly focussed and at an ‘appropriate’ level
of scientific detail. ‘Appropriate’ was a judgement by the
TAC, in general it meant that the most favored studies
addressed clear and immediate needs to close information
gaps in the risk assessment (the EIS). As a result, studies on
theoretical ecology or biology were less common. In the
assessments, the biosphere information served 1) to estimate
doses to humans and other biota resulting from potential
radionuclide releases and, 2) to estimate whatever dilution
and dispersion might occur. Although dilution is expected,
the biosphere is not usually conceived to be a protective
barrier. However, certain parts of the environment, and
especially soil, can accumulate contamination over time.
The Seaborn Panel (1998) had few comments about the
biosphere or the way the underlying biosphere research was
reflected in the assessment (described in detail in the
Related Areas section of this background paper).
KEY ELEMENTS
The biosphere is remarkably diverse, and so is biosphere research that is relevant to
HLRWM. To present a concise overview, six key elements are described here in some
detail. This is not to diminish other excellent research initiatives that are also relevant to
HLRWM. The key elements include:
¾ Biosphere research and the risk assessment paradigm – detailing where the research
emphasis is in the context of the overall assessment problem;
¾ How biosphere research is done – illustrating the typical level of detail;
¾ The dualities of biosphere research for HLRWM – describing several ways the
research directions are changing;
¾ Implicit protection of the environment – showing how the intent is to fully protect
all aspects of the environment;
¾ Humans versus non-human biota – demonstrating the largest new research
initiative; and
¾ Continued advances related to humans – showing the continued research activity in
the traditional research directions.
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Biosphere Research and the Risk Assessment Paradigm
The research topics to
support risk assessment
are: source, exposure,
effects and risk.
Biosphere research for HLRWM has been strongly oriented
to risk assessment. Risk assessment has evolved a specific
methodology, and that brings specific information
requirements. Theoretical biological and ecological
research is often not directly required: the research needs for
risk assessment are quite practical. Very often the required
information relates to quantification rather than hypothesis
testing. In other words, the scientific questions are more
like ‘how much of this will happen’ as opposed to ‘will this
happen or not’. To understand these practical research
needs, it is important to relate them to the underlying risk
assessment paradigm. The paradigm includes four
elements: source, exposure, effects and risk.
The source is obviously
the waste, but where it
gets to the environment is
important.
Risk from exposure to contamination is quantified from
information about source, exposure, effects and risk. In
HLRWM, the source to the biosphere is either the
engineered facility or the intervening rock mass
(geosphere). In either case, the important characteristics of
the source are the rate, timing and location of the
contaminant release. It is also important to know the
physical and chemical form of the contaminants. Releases
from surface storage facilities can be very effectively
controlled, provided there is ongoing monitoring and
surveillance, but from closed underground disposal
facilities, they are more problematic. This is where much of
the corresponding biosphere research has been directed, and
where some conceptual differences emerge. Many agencies
assume the biosphere source or entry point from geological
disposal will be solely into the aquatic environment, with
some of the contamination then making its way to the
terrestrial human food chain by processes such as irrigation.
Others, including AECL/OPG (Davis et al. 1993; Sheppard
et al. 1995) assume that at least some of the contamination
will directly enter terrestrial wetlands. There has been some
very interesting research on this, and it is an example of the
use of analog information. The underlying question is
whether a deep source of radioactive material can be
detected at the surface, and this is exactly the same problem
faced by prospectors looking for uranium deposits. There
has been a cross-fertilization of research methods, including
the use of ping-pong balls to sample helium as an indicator
of buried, decayed natural uranium (Gascoyne and Sheppard
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1993).
Most biosphere research
is directed to estimation of
exposure from
contamination.
Exposure describes the transfer of contaminants (or
radiation) from the environment to human or non-human
receptors. This is where the food-chain models are used.
The basis is simple: how much contaminated food, water or
air does a receptor consume? Information on ingestion of
food and water and on inhalation of air for humans and
other biota is relatively abundant from the literature, and so
little research specific to HLRWM is required. Estimates of
expected concentrations in the food, water and air are much
less certain, and this has been and continues to be the major
emphasis in biosphere research for HLRWM. To illustrate,
over 80% of the papers at the last ECORAD conference
were related to exposure (Bréchignac and Howard 2001).
Keeping it simple is a
hallmark … most of the
required data are
measured ratios.
Research dealing with environmental concentrations ranges
from largely physical/chemical processes such as sorption
and dispersion, through to the biological processes such as
uptake and excretion. In all of these, there is considerable
scope for varying levels of detail. At the simplest level,
these processes can be investigated and characterized with
empirical (i.e., measured) ratios, and indeed this is the level
of detail used in assessment models. To illustrate, the
transfer from soils to plants is modeled almost exclusively
as an empirical concentration ratio (CR) that is different for
each radionuclide and location. Research at this level seeks
to obtain more CR values for more settings, to statistically
relate CR to environmental parameters, and to understand
the uncertainty (variation) associated with these empirical
values. The underlying theoretical research on soil-to-plant
transfer of elements (usually nutrient elements or some
heavy metals) is much more sophisticated. Just to illustrate,
the underlying research on plant uptake of iron deals with,
among other aspects:
− the release into the soil of iron-specific chelating and
acidifying agents by plant roots,
− iron diffusion gradients in the root microenvironment,
− microbial populations specific to the root surface,
− symbiotic fungi that invade the root and simultaneously
extract iron from soil,
− the diffusion of oxygen in soil, its consumption by plant
and microbial respiration and its effect on iron
oxidation and solubility,
− chemical reactions of iron with root cell walls, and
− the ability of the plant to transport iron through the root
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to the shoot.
Despite knowing about all of these processes, the
international consensus is that this level of detail is far
beyond the needs for assessment of HLRWM. Indeed,
given that assessments are inhibited by large uncertainties
related to time (thousands of years), HLRWM research on
such uptake details could convey a false degree of certainty.
Despite considerable
recent research on other
types of effects, radiation
damage remains the key.
The effects dealt with in assessment of HLRWM are almost
exclusively related to radiological dose. Physical
disturbances such as thermal effects (nuclear fuel waste
generates some heat) and the presence of HLRWM
structures are considered relatively minor. Chemical
toxicity (as opposed to radiological toxicity) is a possible
consequence from some non-radioactive constituents of
high-level waste, such as boron from borosilicate glass, and
from some very-long-lived radionuclides such as 99Tc, 129I
and 238U. These are dealt with in assessments, and there has
been research effort on chemically toxic impacts of
HLRWM (Bird et al. 1997b).
Interestingly, even though the effects of concern in
HLRWM are radiological, there was almost no research on
radiation effects funded directly by agencies involved with
nuclear waste prior to about 2000. In part, this is because
the ecological data from the 1970’s were considered
sufficiently valid, and in part, because radiological dose to
humans is intensively studied in relation to health and
safety. The very recent interest in radiological effects on
non-human biota has spawned some new research on
radiation effects, and there is a need for more data on effects
to aquatic organisms because they were not often included
in the nuclear weapons related research in the 1970’s.
Is a very low dose
harmful, benign, or
beneficial?
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There remains debate about the significance of low-level
radiation. One argument is that radiation damage has no
lower limit: the ‘linear-effect-no-threshold’ hypothesis says
that there is some level of effect (and risk) at even the
lowest exposure, because there is a statistical possibility that
a single radioactive emission could damage DNA and result
in cancer or genetic damage. Another hypothesis (and there
are several intermediate to these extremes) is that all life
evolved in a higher radiation environment than at present
and has adapted to repair genetic or other damage resulting
from radiation. There is also compelling evidence of
stimulated growth (hormesis) as a result of radiation
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(Luckey 1980). As academic as this debate may be, it has
profound implications for HLWNM because one side could
lead to a ‘no dose increase is acceptable’ position, whereas
the other would lead to a ‘any dose within the range of
normal background is acceptable’ position.
In biosphere research, risk
translates to a need to
characterize natural
variation.
Research on risk is seldom seen as a component of
biosphere research, and there are separate scientific journals
devoted to the examination of the concept of risk. However,
risk entails probability, and there has been biosphere
research to understand the probabilities and uncertainties of
the environment. All biosphere data (also true of any data)
have associated uncertainty, some related to natural
variation (e.g., the average man weighs 70 kg, plus or minus
20 kg), some to uncertainty in measurement (e.g., the rate of
loss of gas from a whole lake is difficult to measure), and
some to uncertainty in the underlying science (e.g., it is
essentially impossible to have a perfect model of a natural
system). Historically, uncertainty was dealt with by
selecting data values that did not underestimate, and
probably overestimated, the effects. This was a purposeful
‘conservative’ bias … a judgment call based on knowledge
about the system. Now, HLRWM programs commonly
emphasize ‘probabilistic assessment’, where best-estimate
values and expected uncertainties are used. In adopting this
approach, it was discovered there is a shortage of
information about the other statistical attributes of biosphere
data. In addition to knowing the average or best-estimate
value, it is now important to measure statistical dispersion
(variation), truncations (impossible upper or lower values)
and correlations to other parameters. In some respects,
these are more important that the averages, because the
extreme values are most important to understand in order to
ensure protection of the environment.
Summary
To summarize, the biosphere research related to HLRWM is
strongly focussed on issues related to assessment. The risk
assessment paradigm divides the process into aspects of
source, exposure, effects and risk. By far the greatest
emphasis has been on research related to exposure, with
some recent effort on effects for non-human biota.
How Biosphere Research is Done
Realism is important,
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because no one knows all
the interactions that may
be important.
do biosphere research as there are researchers. It is beyond
the scope of this paper to attempt to describe how biosphere
research is done in general, but there are some attributes of
biosphere research related to HLRWM that are notable.
− A key one is realism. The research objectives are
generally very practical – will this event (the one being
studied) have an effect on the environment? Such
questions are often difficult to answer with highly
controlled laboratory studies, simply because the real
environment is not highly controlled. Accordingly,
there is considerable effort to conduct research in as
realistic a manner as possible. Outdoor experimental
settings (photo opposite), long-term observations (weeks
not seconds) and locally-relevant organisms are often
preferred.
− Similarly, the data collected tend to be relatively gross
quantities, such as concentration and mass, as opposed
to subtle quantities such as enzymatic activity and
membrane function.
− Statistical analysis is a key component, because as in
most biosphere research, the requirement is to
differentiate an effect (a signal, to use an electronics
analogy) from a great deal of background variation
(noise).
− Because of this large amount of variation and interaction
in the environment, results of research must be qualified:
‘in this setting with this organism we observed this, and
it may be relevant to that setting and that organism
because …’. This ambiguity sometimes frustrates
specialists in other more exact disciplines, but is the
reality of natural systems.
− A distinct attribute is that radioactive substances are
used, so the analytical methods are quite different than
for other contaminants, and sometimes substantially
more sensitive.
Models are an integral
part.
Apart from experimental research, there is a substantial
component of model development as part of biosphere
research. The models range from detailed models designed
solely to learn about processes, through to assessment
models designed to predict unknown situations based on
previous knowledge. In many ways, models have become
part of the scientific method: the model is our hypothesis of
how a system works, and experimental results prove or
disprove that hypothesis.
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Biosphere research is
strongly ‘mission
oriented’.
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What research is undertaken is almost entirely a function of
who is paying. Even at universities, curiosity oriented
research has been only rarely possible in the past several
decades. The opposite is ‘mission oriented’ research, where
the use of the information is clearly established before the
research begins. There is competition among researchers
for financial support, so those with the funds direct the
research. The research is to answer specific questions, and
the questions usually derive from issues raised in the
assessment of possible effects. Today, this underlies almost
all research on biosphere issues, everywhere in the world.
The Dualities of Biosphere Research for HLRWM
The research to assess
potential effects to
non-human biota is quite
different from that for
humans.
In a number of aspects, biosphere research is split, usually
between the traditional approach and a new approach
designed to address a recent topic. These splits probably do
not change the effectiveness of the research, but may appear
as inconsistencies. For example, potential chemical toxicity
is a new topic and is handled differently than the traditional
approach to radiological effects. More notably, the research
on human versus non-human effects is quite different at
present, and this has an interesting and important
implication. As outlined by Sheppard (2001), in order to
deal with the new topic of effects on non-human biota, a
convergence has begun between the rather entrenched
disciplines of radioecology and ecotoxicology. Society is
more familiar with the results of ecotoxicology, because it
leads to the guidelines that control common pollutants such
as household products, sewage, pesticides and heavy metals
(e.g., from the Canadian Council of Ministers of the
Environment). There have been marked advances in
ecotoxicology, such as definitions of what must be protected
in an ecosystem, how to deal with simultaneous multiple
contaminants, and how to interpret the ecological
significance of sensitive biochemical-level responses to
contaminants (Suter et al. 2000). Radioecology will once
again gain significant capability as it adopts methods from
another discipline.
Canada has been a leader
in the research on effects
to non-human biota.
Canada has done some of the ground-breaking research on
the various effects of exposure to radiation of non-human
biota. In addition to the important contribution of the FIG
experiment described earlier, papers from the Canadian
HLRWM program (Amiro 1997; 1995; Zach and Amiro
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1996a;1996b) became cornerstones in the assessment of
effects on non-human biota, especially for their generic
approach to dose calculation for the myriad sizes and types
of organisms. More advances came from the Environment
Canada initiative (under the Canadian Environmental
Protection Act, Priority Substances List) that specifically
used ecotoxicological methods to assess radiological
impacts from nuclear facilities (Bird et al. 2002). A
controversial development here was the challenge to
previous applications of human-focused treatment of the
relative biological effects from alpha emissions (and beta
emissions from tritium). The position taken was that alpha
particles were about twofold more damaging to
survival-based, non-human endpoints than to cancer-based,
human endpoints, and this seems untenable to some
researchers who insist that humans are the most sensitive to
radiation effects. Ironically, much of the information for
effects to humans was derived from non-human
surrogate-animal studies. The data from these studies, such
as with rodents, are often more valid for assessing effects on
similar wild animals than they are for assessing effects on
humans.
Summary
The biosphere research related to HLRWM is changing,
with one direction being towards the more commonly
accepted methods of ecotoxicology. Canada played a
prominent role in the early developments in this direction.
Implicit Protection of the Environment
Is estimation of dose and
risk sufficient to ensure
full protection of the
environment?
To generalize the expectations of the public, it might be
stated that they want to know that soil, water and air will be
protected, now and in the future. The public expects the
preservation of biological diversity and the sustainable
management of terrestrial, aquatic, and atmospheric
resources. Unfortunately, the messages provided by
assessments to date have been more convoluted. The results
are summarized as an abstract ‘dose rate’, and then this is
compared to an even more abstract ‘risk’, and risk can never
be zero. The question becomes: does this convoluted
process ensure the sustainability and complete protection of
the environment?
Biosphere issues for waste
storage are better
To begin, it is important to establish what we mean by
“sustainability and complete protection of the environment”,
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understood than the
far-future effects from
disposal, but research
needs to address both
phases.
why dose and risk are described, instead of the many other
environmental insults (e.g., contamination, dust, noise,
physical disruption) considered in most environmental
assessments. In general, the environmental effects can
result from two different phases of HLRWM. In the storage
phase, it is assumed that the waste is managed for decades
by a competent agency that can and will detect and fix any
problems that occur. This implies the waste is easily
monitored and can be retrieved. The disposal phase is when
the waste is put in a final permanent location. Both phases
must be assessed for environmental effects, but the
difference is that during storage it will be possible to detect
and mitigate effects before they are serious, whereas in
disposal this cannot be assured. Storage has been underway
for many years, there is an excellent track record of
environmental safety, and so there is little perceived need
for biosphere research. In contrast, disposal of high-level
waste is unproven, so research is more obviously required.
In fact, the information needs for both phases are similar,
the assessment capabilities for both must be consistent, and
so there is need for biosphere research for both storage and
disposal.
Only the most mobile
contaminants could
escape successful waste
disposal … this helps set
priorities.
The very definition of a successful high-level disposal
facility is that it must isolate the waste from the
environment for centuries or millennia. Even then, only
minor failures and very small leakages would be considered
acceptable. As a result, only the most soluble and most
mobile contaminants could escape, and only in small
amounts, from a successful facility. This places the
biosphere research emphasis squarely on the mobile
radioactive contaminants.
In an effort to ensure all
possible contaminant
dispersal processes are
understood, there has
been research into even
rather obscure processes.
Mobile contaminants have the potential to spread to all parts
of the environment (see schematic). This is the basic
assumption in the models used to predict effects related to
HLRWM. Indeed, this assumption is so strongly
established that there is a portion of biosphere research
devoted to finding and evaluating the ‘new’, more obscure
pathways. These are new in the sense that they are seldom
considered as contamination pathways, they are otherwise
common events. In the Canadian program, as an example,
there were experiments and models to quantify obscure
pathways such as:
− contaminated water dispersed into indoor air by
humidifiers and showers (Johnston and Amiro 1994);
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− contaminants from vegetation dispersed into air by
biomass combustion, including fuel, agricultural and
wild fires (Amiro et al. 1996);
− contaminants in soil inadvertently ingested from soiled
hands or as soil retained on vegetable foods even after
washing (Sheppard 1994);
− contaminated aquatic sediments converted to
vegetable-garden soil (Bird et al. 1997a); and
− meat products contaminated because livestock animals
inhaled contaminated air (Zach et al. 1996a).
In general, there has been considerable research on the
extent to which radioactive contaminants disperse in the
environment. As a result, the tools and some data are
available to evaluate the protection of water, air and soil
quality; the preservation of biological diversity; and the
sustainable management of water bodies, shoreline
resources, atmospheric resources, and terrestrial resources.
However, by the nature of the problem, the standards to be
met will relate to radiological dose and risk, despite those
being abstract concepts to the lay public.
The number of pathways that can be modeled in an
Many pathways must be
well researched to reliably assessment has progressively been expanded, but very often
the new pathways do not add significantly to the assessment
assess possible effects.
results. Typically, one or two pathways completely
dominate an assessment, and all others are insignificant
additions. However, this does not necessarily simplify the
assessment, because different pathways dominate for
different radionuclides, different time periods and different
receptors, even if the source remains unchanged. As a
result, biosphere research must continue to address a broad
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spectrum of possible pathways. As an example, the
dominant pathway for 14C is often the water-fish-human
pathway and for 36Cl it is often the soil-plant-human
pathway, and 14C will tend to be more important earlier in
the assessment time than 36Cl. Clearly, many pathways
must be well researched to reliably assess possible effects.
Summary
The HLRWM biosphere research to protect the environment
is directed toward the most mobile radioactive
contaminants, because the waste storage and disposal
facilities will be required to have exceptional integrity and
will retain anything less mobile. Radiological dose and risk
are the state-of-the-art quantities to consider for radioactive
contaminants. There has been a long-standing assumption
that radioactive contaminants will disperse to all parts of the
environment. There has been research not only into the
obvious processes (e.g., irrigation of garden plants with
contaminated water), but also into some rather obscure
processes (e.g., release of contaminants to air from water
used in household humidifiers). It would seem reasonable
to assume, certainly it was the intent of the researchers
involved, that the methodology is in place to ensure
protection of all aspects of the environment. This is not to
preclude the need for improvements in accuracy and the
need for more data to better characterize the variation to be
expected.
Humans Versus Non-Human Biota
The former assumption
was: protect humans and
all else will be protected.
Prior to the early 1990s, the mantra of the nuclear industry
for protection of the environment was people-oriented and
simple: humans are the species most sensitive to
radiation - protect humans and all other species will be
protected. This position was promulgated by the highest
authorities among the international nuclear agencies (ICRP
1977). Since then, this assumption is no longer blithely
accepted, perhaps for three reasons: 1) scientists do not like
absolute statements and are more willing to believe that
there are always exceptions, 2) it is easy to conceive of a
contaminated environment where humans are not present
(such as a lake bottom) but where other biota will be
exposed, and, perhaps cynically, 3) radioecology as a
discipline needed a new topic because human-related issues
seemed to be solved.
The assumption had some
There was reasonable basis for the assumption that
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merit, but the present
consensus is that it must
be examined in detail.
protection of humans ensured protection of everything else.
¾ Humans live long enough that cancer is a more common
occurrence in humans than in other biota. The link
between radiation and cancer is well established.
¾ In general, as one considers increasingly complex
organisms, there is a greater sensitivity to radiation
(Whicker and Schultz 1982). Certainly micro-organisms
and insects can be remarkably resistant. It was easy to
accept that humans might be inherently most sensitive.
¾ Society is concerned about the protection of each
individual human, but is more willing to accept that
most non-human biota need only be protected at the
level of population. Thus for example, cancer in a few
older fish may not be an issue as long as there are
enough other mature fish in the population to ensure
sustainable reproduction. An obvious exception would
be endangered species where each individual has
exceptional value.
¾ The food-chain models to assess effects on humans
could be extended to assume that people are exposed to
almost all possible environments. To further the
previous example, people could be exposed to
contaminated lake-bed sediments because of fishing and
dredging.
¾ There is such diversity among non-human biota that a
thorough investigation, at least to the level of detail that
was the norm for the assessment of humans, is clearly
impossible.
Although these are reasonable arguments, after ten years of
debate, they are no longer considered adequate without
proof. There is a very large international effort underway
now to evaluate the potential effects of all nuclear facilities
on non-human biota (Bréchignac et al. 2003; Egan et al.
2001).
The diversity of
non-human biota pushes
radioecology well beyond
the previous norms.
A major challenge is presented by the diversity of
non-human biota: the size range among legged animals
alone spans 10 trillion-fold (from tardigrade to moose, see
photos). The previous methods in radioecology required
one to know the size, food habits and ingestion rates of the
organisms, and it is not a reasonable expectation to carry
that methodology forward to all biota. Radioecology must
adapt the methodologies of ecotoxicology (Sheppard 2001),
where protection of all biota has always been the nominal
goal. In doing this, information from many other biological,
and especially ecological, disciplines will be needed.
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At present, dose
thresholds for non-human
biota are about 200-fold
higher than comparable
thresholds for humans.
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Radiological dose continues to be the quantity studied, and
the effects of interest are those related to sustainability of
the population, such as growth, reproduction and genomic
stability. Estimation of dose is potentially complicated,
although the simplifications proposed by Amiro (1997)
seem adequate given the other uncertainties that are part of
the whole assessment process. Some dose response
information is available, and as in ecotoxicology, it will be a
continued research need to systematically quantify the
effects of radiation on different biota in different settings.
To illustrate the state-of-the-art, Environment Canada (Bird
et al. 2002) has recently established that dose rates in the
range of 0.2 Gy a-1 (for fish) up to 2 Gy a-1 (for invertebrates
and birds) are the thresholds below which ecological effects
are unlikely and above which effects may occur. The dose
limit used in Canada for members of the public is, in
equivalent units, 0.001 Gy a-1, 200-fold lower than the
threshold for fish. Based on this, effects on non-human
biota may only be important if they are at least 200-fold
more exposed than are humans. This is entirely feasible, as
illustrated in Appendix B. Note that the average natural
background dose for humans, estimated by Health Canada
and including radon, is 0.002 Gy a-1, and that the
0.001 Gy a-1 dose limit is in addition to any background
dose.
An important underlying fact that markedly simplifies the
assessment of the effect of radionuclides on all biota is that
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almost none of the radionuclides biomagnify. That is, in
contrast to organic hazardous materials such as the
insecticide DDT, radionuclide concentrations in the body
seldom increase as one moves up the trophic levels of the
food chain. This has an important implication, as it means
that a top predator is not necessarily at greater risk than an
herbivore, and that the details of the number of trophic
levels between the source and the organism of interest is not
a priority.
Summary
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There has been a major paradigm shift, from a grand
statement that to protect humans was sufficient, to a more
detailed investigation of exceptions to that assumption.
This topic is the subject of a massive international effort,
and rapid advances can be expected. At present, it would
appear that non-human biota are more important in settings
where humans are not specifically exposed, but if humans
are present then protection of humans is probably sufficient
to protect the whole environment.
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Continued Advances Related to Humans
The key HLRWM
radionuclides include
some that are isotopes of
biologically essential
nutrients.
Although the science related to the possible effects of
present-day nuclear facilities on humans is fairly mature, the
assessment of HLRWM is somewhat different and has led
to specific advancements. One of the key areas has been a
shift in emphasis among radionuclides. The dose from
present-day releases are dominated by 3H, 131I, 137Cs and Uand Th-decay series (the emphasis on these is illustrated in
Table 1). In HLRWM, the emphasis has shifted to
very-long-lived and very mobile radionuclides, so that 14C,
36
Cl, 99Tc and 129I are prominent. Three of these (14C, 36Cl
and 129I) are isotopes of common, stable, life-essential
elements. This implies biological regulation in the uptake
of these three radionuclides, and significant modification of
uptake because of differences in the stable element
concentrations4. The older biosphere models do not fully
account for these additional influences. Canada was a
leader in deploying models that account for the ratio of
radioactive/stable-element concentrations, and other
HLRWM agencies such as ANDRA in France and Nirex in
the UK are just beginning to follow this lead. The necessary
underlying assumption is that the radioactive and stable
isotopes behave in the same way, and there is strong
evidence that this is a reasonable assumption for the more
massive elements (14C and heavier).
Table 1. Numbers of papers in the Journal of Environmental Radioactivity from 1995 to 2002, in
decreasing order, that cited the following elements and associated radionuclides in the title,
keywords or abstract (from Sheppard 2003).
Element
#
Element
#
Element
#
cesium
345
plutonium
71
iodine
22
uranium
134
thorium
49
technetium
20
strontium
119
tritium
28
carbon (14C only)
12
radon
109
cobalt
26
neptunium
7
36
lead
74
manganese
24
chlorine ( Cl only)
1
Biochemical processes cannot effectively tell the difference between stable and radioactive isotopes
(heavier than 14C) so, for example, deficiency in stable iodine (127I) in the environment could well result in
enhanced uptake of iodine in general, which could include enhanced uptake of the radioactive 129I.
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The nearly universal focus
on the human critical
group as a self-sufficient
agrarian community lacks
realism.
Virtually all HLRWM assessments to date have dealt with a
human receptor described as the ‘critical group’ or
alternatively the ‘potentially exposed human groups’. This
concept is intended to define a group of people in the worst
place at the worst time, with habits that tend to maximize
their exposure to radionuclides. Typically, the critical group
resembles a small rural community with a higher degree of
self-sufficiency than is common today. One problem with
this is that the interested public does not easily identify with
such abstract life-styles, and research has been done to make
the critical group less abstract (Zach et al. 1996b). Another
is that the critical group concept tends to focus the research
efforts away from what might be more plausible exposure
scenarios. As an example, if the HLRWM facility is located
in a relatively remote area, then the roads and infrastructure
built to service the facility may attract a community that
with time evolves into a town or urban setting. Although it
is argued that exposure in an urban setting is less than for a
self-sufficient agrarian setting, this fairly plausible evolution
of the environment toward urbanization is not often
considered. There is biosphere research on urban
radionuclide behaviour, most of it related to Chernobyl and
present-day nuclear facilities (Betti, 2000; Nicholson and
Hedgecock 1991), but this is seldom applied to HLRWM.
If the assessment emphasis
moves to include
collective dose (the sum of
dose to all people), then
several aspects of the
problem will change.
Related very closely to the assessment of urban settings,
assessments to date expend most effort on the dose to the
individual. This may be reasonable if the individual is truly
a member of the critical group who are maximally exposed.
However, such an approach would favor HLRWM concepts
where dilution and dispersion are maximized. Such an
outcome is certainly not intended nor conceived as being
helpful. An assessment alternative is to consider the
collective dose, i.e., the sum of doses for all individuals in
the affected area, or even all individuals in the world. The
idea is attractive because it sums the dose from all
contamination released by a facility, regardless of how
much it was diluted or how far it went. The major problem
is that there is no consensus on how high a collective dose is
too high. Additionally, collective dose tends to increase as
the size of the area considered increases, because it
encompasses more individuals. For example, if 14C from a
waste facility spread all around the world in the natural
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carbon cycle (as it will eventually), there would be a very
small, but finite (quantifiable), dose to all people. Even a
very small dose to 600 million people5 would add up to a
seemingly large collective dose. This somewhat
open-ended definition of the number of affected people (or
other biota) increases uncertainty in the interpretation of the
value. If collective doses were considered, then an urban
centre may well be more critical than the agrarian critical
group. The research needed in this case is more
philosophical than biological … how does one decide how
many ‘person-sieverts’ (the unit of measure for collective
dose) is too many?
Assessing the spatial
distribution of
contamination in the
biosphere is not yet a
priority in HLRWM
programs … this is
expected to change.
There is also research to improve spatial analysis of
HLRWM, and this is related to the concept of collective
dose. In recent years, geographical information systems
(GIS) and a number of related technologies have provided
tools to more effectively evaluate the spatial extent of
contamination (both along the surface and with depth).
Although progress has not been rapid in applying this to
prediction of future spread of contamination, there is a trend
in that direction (Nirex 1999). To put the issue into context
in the Canadian setting, one of the criticisms from the
HLRWM hearings in the mid-1990’s was that the
assessment did not consider the potential for contamination
of a downstream delta, but only considered the immediate
area around the source. The counter-argument was that the
downstream setting would necessarily be more dilute, so
less critical than the source setting. Regardless of the
validity of this argument, there is an expectation that further
assessments will deal more explicitly with spatial
contamination, either for varied critical groups or for
estimation of collective dose. Research on this is not a
priority at present in most HLRWM programs.
It is difficult to make
believable estimates of
radiological effects over
time periods long enough
to include future
glaciation.
Another dimension that is difficult to deal with in HLRWM
is the change in the environment with time. This was cited
as a specific shortcoming of the Canadian program in the
Seaborn Panel (1998) report. The environment can change
in many ways, and climate has received the most attention.
Although the public is now aware of global warming, the
future onset of glaciation is the change dealt with in more
detail by most HLRWM programs. Glaciation has obvious
implications on the environment. The radiological dose
during full glaciation, when ice would cover most of what is
5
600 million people is one estimate of the world population in 2002.
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now Canada, is not assessed because it is not considered the
dominant stress compared to kilometer-thick ice sheets.
However, in the cold climates before and after full
glaciation, radiological dose is potentially important, and
this has been assessed. No one knows what the composition
of the environment or the role of humans will be in these
environments. However, there is evidence that the uptake
and transfer of radionuclides may change in cold versus
contemporary, warm climates. For example, ANDRA
(2001) concluded that, for cesium at least, there are 20-fold
higher concentrations in arctic and boreal plant species than
in temperate species, and there was a similar trend for
animals. For both plants and animals, this effect may be
more related to the fact that different species thrive in colder
climates, rather than an effect of temperature or climate
itself. There is a significant challenge to make such
estimates believable to the public, who are aware that
climate is now changing and climate prediction is very
unreliable.
Summary
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Progress continues on the improvement of the safety
assessment methodology for humans in the biosphere.
Among other aspects, new models have been developed that
account for the fact that key HLRWM radionuclides are also
common and biologically essential elements, the concept of
the critical group has been revisited, and changes in the
environment in space and time are being addressed.
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GLOSSARY
Alpha emissions are one of three major types of radioactive emissions. The others are
photon (gamma and x ray) and beta (electrons). Alpha particles are massive in
comparison to the others, and cause much more biological damage per emission than
either photon or beta.
Biological regulation implies that the biochemistry of the organism is genetically
organized so that the organisms can specifically absorb or excrete a substance based
on physiological needs. It often implies the use of metabolic energy by the organism
to activate regulation mechanisms such as specific enzymes. For example, iodine can
be deficient in the environment and organisms will very effectively concentrate it in
the thyroid where it is an essential nutrient.
Biomagnify is the situation where the concentration of a contaminant increases from prey
to predator, with the result that top predators are most at risk (e.g., eagles from DDT
in their food chain). This is not the case with most radionuclides.
Biota refers to anything living, including micro-organisms, plants and animals.
Collective dose is a summation of the doses received by all individuals in a group. For
example, if the radiological dose to each individual in a group is 10 Sieverts, and
there are 100 individuals in the group, the collective dose is 1000 Sieverts.
Competent agency is intended to mean an organization with the financial, technical and
social capabilities to manage, in this case a waste facility, in a manner that meets high
standards for human and environmental protection.
Conservative is a word that reflects a simple concept but is very difficult to use
accurately in a risk assessment. The concept is that, given some uncertainty, one
makes decisions in the assessment that should lead to an overestimate, as opposed to
an underestimate, of dose or deleterious effect. The difficulty in application is that it
is not always obvious which decision will be conservative in all cases.
Developmental instability in the ecological sense is an attribute of populations of
individual organisms that have the same genetic background, but that show enhanced
variation among the individuals resulting from differences in their rates and modes of
development. Developmental instability results from stress, and may arguably lead to
genetic changes that allow adaptation to the stress.
Effects is a term used very frequently related to environmental issues, and it is intended
to be as general as its common meaning. During the assessment of any project with
environmental connections, the ‘effects’ discussed can be any change since the
project began, including the results of stressors such as toxicity, radiation, noise,
temperature and dust. Effects do include changes that appear to enhance the
environment, such as stimulated growth, because inevitably there will be
accompanying negative effects. Impact is a synonym in this context, because even
apparently positive effects will always have a negative component.
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Endpoints in ecotoxicology refer to the biological process that is specifically affected by
a contaminant. Lethality is an endpoint, but preferred endpoints deal with growth rate
or reproductive capacity.
Food chain describes in simple words, who eats whom. Food chains usually start with
plants that capture energy from the sun, the next link in the food chain are herbivores
that eat plants, followed by carnivores that eat herbivores. The human food chain has
the same structure, with agricultural production of foods playing the dominant role.
Genomic stability is the degree to which subsequent generations have the same DNA as
the previous generations, evolution is based on there being some genomic instability
(change), but too much instability is considered evidence of stress.
Half life is the rate of decay of a radionuclide, the time it takes for half of the
radionuclide present to decay to another radionuclide or stable element.
Hormesis is where an organism or ecosystem will have an apparently positive response to
a low dose of something that is normally considered a stressor. Many
pharmaceuticals work this way: a low dose is beneficial a high dose is toxic.
Radiation hormesis is reported to occur, although this is controversial.
Impact is a synonym for ‘effects’ in this context (see ‘effects’ above), because even
apparently positive effects will always have a negative component or impact.
Individual as used for biota in the assessment context has exactly the same meaning as in
common use: one individual is one organism (including human), without regard to the
population to which it belongs.
Pathway in this context is the route contaminants might follow as they move from a
source (the waste storage or disposal facility) to a susceptible receptor such as a
human or other organism.
Population is a number of individuals of the same species within a specified location that
is large enough that it can successfully reproduce and be sustainable, assuming the
environment remains unchanged with time.
Probabilistic assessment is a technique where instead of making one estimate of an
environmental outcome (called a deterministic assessment), one makes thousands of
estimates, each one a different but reasonable reflection of a possible outcome. There
are various ways to do probabilistic assessments, but the intended result is a
indication of the probability associated with each level of outcome. A typical result
might be stated in the form: the dose will be lower than 0.002 Sievert per year in 95%
of the possible cases.
Radionuclides are radioactive forms of elements from the periodic table, the nucleus of
each radionuclide atom will at some (one) time disintegrate (decay) causing an
emission of photon energy and/or particles that can inflict biological damage.
Research is not as easily defined as it may seem. The Webster’s definition is ‘studious
inquiry or examination aimed at the discovery and interpretation of facts, revision of
accepted theories in the light of new facts, or practical application of such new or
revised theories’. The emphasis is on ‘new’ and ‘theory’, which implies information
that is broadly useful. Another definition might be: development of information that
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could be published in peer-reviewed scientific journal. The implication is that,
although many people measure things in the environment, only those measurements
that provide new information about specific theories and that are of interest beyond
the site where they were measured might be called research.
Risk is a common term, but in the assessment paradigm it is a specific meaning that
combines consequence (such as cancer death) and the probability that the
consequence will occur.
Scientific method is the basic approach of science: to develop a hypothesis about a
natural system, followed by experimental or other kinds of tests to prove or disprove
the hypothesis.
Sievert is the unit of measure of dose used for humans (1 joule per kg flesh).
Sorption is taken to imply a range of meanings, from very specific chemical exchange
reactions on surfaces through to any net effect of a variety of chemical and physical
processes whereby a contaminant in solution becomes associated with insoluble
solids such as soils or sediments.
SWOT (strengths, weaknesses, opportunities and threats) analysis is a management tool
used periodically to assess and redirect activities, largely by causing these attributes
to be listed and recognized.
Tardigrade is a very small, soil-dwelling invertebrate, as small as 50
m (10-6 m) long.
Tools in the assessment context refers to models or ways to compute the effects resulting
from specific processes.
Trophic levels refer to, in simple words, who eats whom. A higher trophic level feeds on
a lower trophic level, and collectively the trophic levels make up a ‘food chain’ (or
‘food web’ in situations where the trophic levels are not necessarily one after
another).
Uptake is a general term used to describe the processes by which a living organisms
absorbs materials and contaminants from the environment.
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RELATED AREAS
Developments in Canada since the Seaborn Report
The Canadian HLRWM program managed by AECL completed an assessment and
submitted it to public hearings in 1993/94, which culminated in the Seaborn Panel (1998)
report. Several follow-up research opportunities were undertaken during this four-year
period, on very specific issues. These included 36Cl (a radionuclide discovered to be
present in greater amounts than previously thought), loss of iodine and carbon as gases
from soil, and effects of climate change. Similarly, some international collaboration
work was still ongoing. The specific reports are listed in Appendix A, under the
following categories:
−
−
−
−
−
Biosphere evolution, onset of glaciation and climate change;
Understanding of underlying processes;
Ecological effects assessment and non-human biota;
Improvements to risk assessment approaches with respect to the biosphere;
Special risk assessment models for 14C, 36Cl and 129I;
− Updates to parameter values – iodine, chlorine, carbon; and
− Supporting research for biological and biosphere connections with the geosphere.
Since 1998, there has been continued effort on specific biosphere aspects of the models
used for assessment, most quite recently (2001-2003). These more recent developments
include:
−
−
−
−
a thorough review of the biosphere model;
a new soil model;
new parameter values for 129I, 36Cl and 237Np; and
recommendations for non-human biota indicator species.
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International Developments in the Last Decade
The HLRWM programs around the world are in varying stages, and each has a unique
approach to the process of establishing a facility. The United States has chosen a location
at Yucca Mountain, so that the corresponding biosphere effort can be fairly specific to the
expected discharge location in the Amargosa Valley. For example, they have surveyed
the habits of people in the Valley. France has focussed on an underground laboratory site
near Bure that may evolve into a storage or disposal facility, and so they are similarly
quite specific and have funded research on soils in the region. Many others do not have
specific sites on which to focus and so remain, as in the Canadian program, fairly generic.
As an example, Nirex in the United Kingdom have continued their emphasis on
landscape evolution, using 2D and 3D models and detailing the expected effects of
glaciation. Although not necessarily comprehensive, the following table lists some of the
biosphere-related activities of the past decade.
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Program - Model emphasis
Agency
UK – Nirex Climate change, ice sheet
R&D and Experimental emphasis
France ANDRA
Radionuclide mobility and plant uptake, update of
parameter values (Tc, U, I, Pa, Se, Cs, Cl)
Site-specific soil characterization and Kd studies
Speciation and phytoavailability of Ni, Zr
Role of microbes (Se, Tc)
Update of cold biosphere parameter values
U toxicity literature review
Role of soil organic matter on fate of Tc, I and Cl
Soil transport of Chernobyl nuclides
Studies on redox and radionuclide movement down
from the biosphere in vertical fractures
Inclusion of non-human biota
Natural analogue study of a peat bog
Compilation of site-specific values
Investigation of the geosphere-biosphere interface
Studies on sea-level changes and glaciation impacts
Sweden –
SKI or
SKB
USA –
USDOE/
MOE
modelling
Soil transport, including 3D
modeling and uncertainty
analysis
Landscape modelling
Improved models for Cl-36 and
C-14
Biosphere and soil evolution
and climate change
Migration through natural redox
interfaces (Se)
Modelling deep groundwater
Transport of Chernobyl
nuclides
More holistic approach to
biosphere evolution through
modeling of various
landscapes – coastal, bog
and agricultural, well, lake
and running water
Model validation through
BIOMOVS, VAMP and
PSAC code comparisons
Attention to model validation
for C-14
More attention given to the
biosphere model in the last
three safety assessments
Development of GENIIS,
evaluation of FEPS
Switzerland Development of TAME –
Terrestrial-Aquatic Model of
- Nagra
the Environment
Participation in BIOMOVS and
BIOMASS
Consideration of climate
change
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Soil leaching and plant uptake lysimeter study for model
validation
Climate analogue locations
Potential Exposed Groups
Identification of the critical group and receptors of
interest, groundwater usage and diet studies,
Compilation of extensive baseline data for the Yucca
Mountain site,
Transfer parameter values,
Climate change, erosion and leaching under desert
conditions
Development of an improved database, especially for
sorption.
Diet definition based on present and historical data, and
with an energy balance limit.
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Convergence with Research Related to Other Hazardous Wastes
The objective for both HLRWM and management of other hazardous wastes such as
heavy metals and man-made organic compounds is much the same: to protect the
environment. The same risk assessment paradigm of source/exposure/effect/risk is used
for both. There is a historical difference in approach. Sheppard (2001) described the
radioecology approach as top-down, and the ecotoxicology approach as bottom-up.
Starting from a strong position in the protection of humans from radionuclides, the
radioecological top-down approach led to publication of international consensus
dose-limits for all non-human biota, and then for classes of non-human biota. These
remain a preferred benchmark in many programs worldwide. There continues to be
research effort to define, for example, the ‘reference organism’ comparable to the
‘reference man’ used to date in radioecology (Bréchignac et al. 2003). In contrast, the
basic approach in ecotoxicological assessment tends to be bottom-up (Suter et al. 2000).
After defining a very specific environmental feature to protect, an ecotoxicology
‘assessment endpoint’ is defined. Almost inevitably, there are no data for the effects of
the contaminant of concern on the chosen assessment endpoint. This gap is bridged, for
assessment purposes, by defining a ‘measurement endpoint’ which is an organism,
endpoint and exposure characteristic that can be used as a surrogate for the assessment
endpoint. Surrogates are not perfect, so adjustment factors are applied to ensure that the
measured effects data will not underestimate the toxicity to the assessment endpoint in
the field. Clearly, the top-down and bottom-up approaches can yield the same results.
They can be based on the same data. Perhaps the key difference is in how they are
perceived by the regulators, the public and the environmental non-government
organizations. The top-down approach carries the perception that details may be
overlooked to achieve a sweeping recommendation. It has aspects of an opaque ‘trust us,
we are experts’ position. The bottom-up approach can convey the perception that details
and site-specific issues are considered. The assumptions may be more transparent. The
bottom-up approach appeals to an ecologically democratic perspective, where humans are
considered only part of the ecosystem. It may be the only useful approach when it
becomes important to protect valued non-human individuals, such as individuals of
endangered species and domestic pets. It is significant to note that the bottom-up
approach has been used for nuclear facilities by Canadian Nuclear Safety Commission
staff seconded to Environment Canada (Bird et al. 2002), and thus it is the present norm
in Canada.
There are other reasons why convergence may be beneficial. In terms of size of research
effort, other hazardous materials are studied much more extensively than are HLRWM
radionuclides. The resulting advancements in ecotoxicology will be beneficial to
radioecology. Examples include:
− use of body-size to extrapolate exposure and effects data from one organism to
another (discussed for 129I by Macdonald 1996),
− attention to the roles of chemical speciation and natural complexing agents on
exposure (discussed for 129I by Sheppard 1996), and
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− how to deal with reported effects on biochemical endpoints (biomarkers) that do not
have a clear relationship to ecological sustainability.
The United States Environmental Protection Agency (EPA) is a leader in dealing with
hazardous waste, and has a policy to broadly share its technology. Many agencies in
Canada and throughout the world use EPA models because, even when they are not
state-of-the-art, there is precedent in their use and they are freely available. For example
some toxicity databases, risk calculators and ecological benchmark data exist for use on
national scales (http://risk.lsd.ornl.gov/rap_hp.shtml;
http://www.epa.gov/enviro/index_java.html; http://star.eea.eu.int/asp/default.asp;
http://www.tera.org/iter/). In addition, the U.S. Department of Agriculture, the U.S.
Department of Commerce and its subagencies, such as the National Oceanic and
Atmospheric Administration, the U.S. Department of Defence, the Department of
Energy, Department of Health and Human Services, including its National Institute of
Environmental Health Sciences all contribute to the Committee on Environment and
Natural Resources Interagency Research and Development
(http://www.ostp.gov/NSTC/html/enr/enr-apb.html) Other countries offer similar
resources, and it is logical that, to the extent possible these be adopted for HLRWM.
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How could the impact of HLRWM biosphere research be enhanced?
The biosphere research for HLRWM and other nuclear activities has strengths,
weaknesses, opportunities and threats, the ingredients of a SWOT analysis and an
indication of where enhancements are possible. The following SWOT analysis is
simplified to a few points, and capsulizes much of what was discussed in this position
paper.
Strengths
- large body of scientific literature from over 50 years of research
specific to radionuclides and radiation in the environment;
- generally good history of environmental protection in the
nuclear industry (there are few cases of effects where none were
predicted); and
- international consensus for protection of humans, and a
developing consensus for the protection of non-human biota.
Weaknesses
- HLRWM issues are not as well researched as are other issues in
the nuclear environmental area;
- radioecology, the study of radionuclides and radiation in the
environment, is a declining discipline especially in North
America, so there is loss of capacity; and
- there some resistance internationally to convergence with
ecotoxicology methods, despite the fact that radioecology has
always adopted information from other disciplines.
Opportunities
- to better integrate basic climatology, geography and ecology
into models of the evolution of the environment as it affects
radionuclides;
- to engage the public by making the assessment outputs more
tangible and identifiable; and
- to develop analogues and large-scale biosphere demonstration
experiments to test and illustrate the assessment capabilities
Threats
- nuclear waste disposal is postponed past when there remains a
viable and competent nuclear environmental skill capacity, or in
some other way essential information is lost.
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REFERENCES
AEA. 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer
in Temperate Environments, IAEA Technical Reports Series No. 364. Vienna.
AECL. 1994. Environmental impact statement on the concept for the disposal of
Canada’s nuclear fuel waste. Atomic Energy of Canada Limited, report AECL10711, COG-93-1.
Amiro, B.D. 1995. Radiological dose conversion factors for generic plants and animals.
Atomic Energy of Canada Limited, Technical Record TR-658. COG-95-512.
Amiro, B.D. 1997. Radiological dose conversion factors for generic non-human biota
used for screening potential ecological impacts. Journal of Environmental
Radioactivity, 35: 37-51.
Amiro, B.D. and S.C. Sheppard. 1994. Effects of ionizing radiation on the boreal forest:
Canada's FIG experiment, with implications for radionuclides. The Science of the
Total Environment 157: 371-382.
Amiro, B.D., S.C. Sheppard, F.L. Johnston, W.G. Evenden and D.R. Harris. 1996.
Burning radionuclide question: What happens to iodine, cesium and chlorine in
biomass fires? The Science of the Total Environment, 187: 93-103
ANDRA. 2001. Selection of transfer parameter values for three cold biospheres: Boreal,
cold steppe and tundra for cesium. Agence nationale pour la gestion des déchets
radioactifs, report C RP 0ECM 01-03/A, Paris, France.
Baes, C.F., III, R.D. Sharp, A.L. Sjoreen and R.W. Shor. 1984. A review and analysis of
parameters for assessing transport of environmentally released radionuclides through
agriculture. Oak Ridge National Laboratory Report, ORNL-5786.
Baker, D.A. 1977. User guide for computer program FOOD. Battelle Pacific Northwest
Laboratories Report, BNWL-2209.
Betti, B. 2000. Environmental monitoring of radioisotopes by mass spectrometry
and radiochemical methods in urban areas. Microchemical Journal 67:363-373
BIOPROTA web link: http://www.andra.fr/bioclim/links.htm
Bird, G.A., J.C. Tait and W.J. Schwartz. 1997b. Radiological and chemical toxicity of
used CANDU fuel. Atomic Energy of Canada Limited Report, TR-767,
COG-96-582-I.
Bird, G.A., P.A. Thompson, C.R. Macdonald and S.C. Sheppard. 2002. Ecological risk
assessment approach for the regulatory assessment of the effects of radionuclides
released from nuclear facilities. IAEA Third International Symposium on the
Protection of the Environment from Ionising Radiation, Darwin, Australia, July 2226.
Proprietary & Confidential
37
ECOMatters Inc.
Nuclear Waste Management Organization
Bird, G.A., W.J. Schwartz, M. Motycka and J. Rosentreter. 1997a. Behaviour of 60Co
and 134Cs in a Canadian Shield lake over five years. Atomic Energy of Canada
Limited Technical Record, TR-781, COG-97-166-I.
Bréchignac, F and B.J. Howard. 2001. Proceedings of the International Congress,
France, September 3-7, 2001. Radioprotection - Colloques, 37(C1); Radioactive
Pollutants Impact on the Environment". Institut de Protection et de Surete Nucleaire
Collection, EDP Sciences, Les Ulis, France.
Bréchignac, F., G. Polikarpov, D.H. Oughton, G. Hunter, R. Alexakhin, Y.G. Zhu, J.
Hilton and P. Strand. 2003. Protection of the environment in the 21st century:
Radiation protection of the biosphere including humankind. Journal of
Environmental Radioactivity (in press).
CSA (Canadian Standards Association). 1987. Guidelines for calculating derived release
limits for radioactive material in airborne and liquid effluents for normal operation of
nuclear facilities. Canadian Standards Association Report, CAN/CSA-N288.1-M87.
Davis, P.A., R. Zach, M.E. Stephens, B.D. Amiro, G.A. Bird, J.A.K. Reid, M.I.
Sheppard, S.C. Sheppard and M. Stephenson. 1993. The disposal of Canada's
nuclear fuel waste: the biosphere model, BIOTRAC, for closure assessment.
Atomic Energy of Canada Limited, AECL-10720, COG-93-10. Chalk River,
Ontario, Canada.
Desmet, G., P. Nassimbeni and M. Belli (editors). 1990. Transfer of Radionuclides in
Natural and Semi-Natural Environments, Elsevier Applied Science Publishers, New
Yor, USA, 693pp.
Dugle, J.R. 1986. Growth and morphology in balsam fir: effects of gamma radiation.
Canadian Journal of Botany 64: 1484-1492.
ECORAD web link: http://www.irsn-dpre.com/ecorad/
Egan, M.J., M. Loose, G.M. Smith and B.M. Watkins. 2001. Work in Support of
Biosphere Assessments for Solid Radioactive Waste Disposal, 1. Performance
Assessments, Requirements for Methodology; Criteria for Radiological
Environmental Protection, SSI Report, October 2001, ISSN 0282-4434.
Fletcher, J.F. and W.L. Dotson (editors). 1971. HERMES – A digital computer code for
estimating regional radiological effects from the nuclear power industry. Hanford
Engineering Development Laboratory Report, HEDL-TME-71-168.
Gascoyne, M. and M.I. Sheppard. 1993. Evidence of terrestrial discharge of deep
groundwater on the Canadian shield from helium in soil gases. Environmental
Science and Technology, 27: 2420-2426.
Guthrie, J.E. and J.R. Dugle. 1983. Gamma-ray irradiation of a boreal forest
ecosystem: The Field Irradiator - Gamma (FIG) Facility and Research
Programs. The Canadian Field Naturalist, 97: 120-128.
Hoffman, F.O., C.W. Miller, D.L. Shaeffer and C.T. Garten, Jr. 1977. Computer coides
for the assessment of radionuclides released to the environment. Nuclear Safety 18,
343-354.
Proprietary & Confidential
38
ECOMatters Inc.
Nuclear Waste Management Organization
IAEA. 1992. Effects of Ionizing Radiation on Plants and Animals at Levels Implied by
Current Radiation Protection Standards. Technical Reports Series No. 332,
International Atomic Energy Agency, Vienna, Austria.
ICOBTE web link: http://www-conference.slu.se/7thICOBTE/
ICRP. 1977. Recommendations of the International Commission on Radiological
Protection. Ann. ICRP 26:1-53.
IUR web link: http://www.iur-uir.org
Johnston F.L. and B.D. Amiro. 1994. Household humidifiers as a radiological dose
pathway. Health Physics, 67(3): 276-279.
Kaye, S.V., F.O. Hoffman, L.M. McDowell-Boyer and C.F. Baes. 1982. Development
and application of terrestrial food chain models to assess health risks to man from
release of pollutants to the environment. In Health Impacts of Different Sources of
Energy, Proceedings of an International Symposium, Nashville, TN, 1981, 271-298,
IAEA-SM-254/63.
Luckey, T.D. 1980. Hormesis with Ionizing Radiation. CRC Press, Inc. Boca Raton,
Florida. 222 pages.
Macdonald, C.R. 1996. Ingestion rates and radionuclide transfer in birds and mammals
on the Canadian Shield. Atomic Energy of Canada Limited Technical Report, TR722, COG-95-551.
Moller, A.P. 1998. Developmental instability of plants and radiation from Chernobyl.
Oikos 81: 444-448.
Moore, R.E., C.F. Baes III, L.M. McDowell-Boyer, A.P. Watson, F.O. Hoffman, J.C.
Pleasant and C.W. Miller. 1979. AIRDOS-EPA: A computerized methodology for
estimating environmental concentrations and dose from airborne releases of
radionuclides. Oak Ridge National Laboratory Report, ORNL-5532.
Napier, B.A., R.L. Roswell, W.E. Kennedy, Jr. and D.L. Strenge. 1980. ARRRG and
FOOD – Computer programs for calculating radiation dose to man from
radionuclides in the environment. Battelle Pacific Northwest Laboratories Report,
PNL-3180/UC-70.
NFWA web link: http://www.nwmo.ca/ and http://www.nfwbureau.gc.ca/
Nicholson K.W., and J.B. Hedgecock. 1991. Behaviour of radioactivity from
Chernobyl––Weathering from buildings. Journal of Environmental
Radioactivity 14: 225-231.
Nirex Ltd. 1999. Assessing the long-term future climate of the British Isles in
relation to the deep underground disposal of radioactive waste. Nirex report
N/010, ISBN 1 84029 252 0.
Oleksyk, T.K., M.H. Smith, J.M. Novak, J.R. Purdue and S.P. Gashchak. 2003. High
levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most
contaminated areas in Chornobyl. Journal of Environmental Radioactivity,
submitted.
Proprietary & Confidential
39
ECOMatters Inc.
Nuclear Waste Management Organization
Seaborn Panel. 1998. Report of the Nuclear Fuel Waste Management and Disposal
Concept Environmental Assessment Panel. Canadian Environmental Protection
Agency, Hull, Quebec.
Shaeffer, D.L. and E.L. Ethnier. 1979. AQUAMAN – A computer code for calculating
dose commitment to man from aqueous releases of radionuclides. Oak Ridge
National Laboratory Report, ORNL/TM-6618, Oak Ridge, Tennessee.
Sheppard, M.I., D.H. Thibault and J.E. Guthrie. 1982. Radiosensitivity and the role of
Pinus sylvestris L. in the revegetation of radioactive disposal areas. Environmental
and Experimental Botany 22: 193-198.
Sheppard, M.I., M. Stephenson, D.A. Thomas, J.A.K. Reid, D.H. Thibault, M. Lacroix
and S. Ford. 1995. Aquatic-terrestrial partitioning of deep groundwater discharge
using measured helium fluxes. Environmental Science & Technology, 29: 17131721.
Sheppard, S.C., Gaudet, C., Sheppard, M.I., Cureton, P.M. and Wong, M.P. 1992. The
development of assessment and remediation guidelines for contaminated soils, a
review of the science. (Invited review) Can. J. Soil Sci. 72:359-394.
Sheppard, S.C. 1994. Parameter values to model the soil ingestion pathway.
Environmental Monitoring and Assessment, 34: 27-44.
Sheppard, S.C. 2001. Toxicants in the environment: bringing radioecology and
ecotoxicology together. Invited paper, In: Radioactive Pollutants Impact on the
Environment". F. Bréchignac and B.J. Howard, Eds., pages 63-74, Institut de
Protection et de Surete Nucleaire Collection, EDP Sciences, Les Ulis, France.
Sheppard, S.C. 1996. Importance of chemical speciation of iodine in relation to dose
estimates from 129I. Atomic Energy of Canada Limited, AECL-11669.
Sheppard, S.C. 2003. Technical note - An index of radioecology, what has been
important? Journal of Environmental Radioactivity, In Press.
Sparrow, A.H., S.S. Schwemmer and P.J. Bottino. 1971. Review paper: The
effects of external gamma radiation from radioactive fallout on plants with
special reference to crop production. Radiation Botany 11: 85-118.
SPERA web link: http://www.sci.qut.edu.au/physci/cmhp/radiation/spera/spera.htm
Suter, G.W., R.A. Efroymson, B.E. Sample and D.S. Jones. 2000. Ecological Risk
Assessment for Contaminated Sites, Lewis Publishers, New York, USA, 437 pp.
Technical Advisory Committee on the Nuclear Fuel Waste Management Program (TAC).
1993. Thirteenth annual report. Technical Advisory Committee Report, TAC-13.
Available from Prof. L.W. Shemilt (Chairman), McMaster University, Hamilton,
Ontario, L8S 4K1.
Whicker, F.W. and V. Schultz. 1982. Radioecology: Nuclear Energy and the
Environment, Volume II. CRC Press, Inc. Boca Raton, Florida.
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Zach, R. and B.D. Amiro. 1996a. Dose prediction for plants and animals - Nuclear fuel
waste management. Proceedings of the CNS/CRPA Symposium on Non-human
Biota. Ottawa, December 1-2, 1996.
Zach, R. and B.D. Amiro. 1996b. Development and application of an environmental
assessment methodology. Proceedings of the International Symposium on Ionization
Radiation. Stockholm, May 20-24, 1996.
Zach, R., Amiro, B.D., Bird, G.A., Macdonald, C.R., Sheppard, M.I., Sheppard S.C., and
Szekely, J.G. 1996a. The disposal of Canada's nuclear fuel waste: A study of inroom emplacement of used CANDU fuel in copper containers in permeable plutonic
rock. Volume 4: Biosphere model. Atomic Energy of Canada Limited Report,
AECL-11494-4, COG-95-552-5.
Zach, R., J.G. Szekely, G.A. Bird, W.C. Hajas, C.R. Macdonald and S.C. Sheppard.
1996b. Alternative human characteristics and lifestyles in the BIOTRAC biosphere
model for assessing Canada’s nuclear fuel waste disposal concept. Atomic Energy of
Canada Technical Report, TR-719, COG-95-542.
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APPENDIX A PAPERS, REPORTS AND CONFERENCE TALKS ON
VARIOUS BIOSPHERE TOPICS FROM THE CANADIAN
PROGRAM SINCE 1992
Biosphere Evolution, Onset Of Glaciation And Climate Change
Papers in this section deal with aspects of climate change as it could affect a waste
disposal facility. The emphasis is on long-term change, specifically the onset of the next
glaciation, which is anticipated in another 10,000 years.
Amiro, B.D. 1997. Potential effects of climatic change on radiological doses from disposal of Canadian nuclear
fuel waste. Health Physics, 72(5): 693-700.
Zach, R., J.G. Szekely, G.A. Bird, W.C. Hajas, C.R. Macdonald and S.C. Sheppard. 1996. Alternative human
characteristics and lifestyles in the BIOTRAC biosphere model for assessing Canada’s nuclear fuel waste
disposal concept. Atomic Energy of Canada Technical Report, TR-719, COG-95-542.
Sheppard, M.I. 1995. Strategy for modelling soil erosion and soil profile development in a landscape for
environmental impact assessments. Atomic Energy of Canada Limited, Technical Record TR-679, COG-95-72.
Sheppard, M.I., B.D. Amiro, P.A. Davis and R. Zach. 1995. Continental glaciation and nuclear fuel waste
disposal: Canada's approach and assessment of the impact on nuclide transport through the biosphere.
Ecological Modelling, 78: 249-265.
Understanding of Underlying Processes
Underlying processes is a rather general term, and the following papers are classed as that
because they tend to explore issues that were not directly used in an assessment, or that
support an assessment in an indirect way.
Amiro, B.D. 2002. Environmental Radioactivity. Encyclopedia of Physical Science and Technology.
3rd edition. Volume 5, pp. 583-599. Academic Press, San Diego, CA.
Echevarria, G., M.I. Sheppard and J. Morel. 2001. Effect of pH on the sorption of uranium in soils. Journal of
Environmental Radioactivity, 53: 257-264.
Voigt, G., E.M. Scott, K Bunzl, P. Dixon, S.C. Sheppard and F.W. Whicker. 2000. Radionuclides in the
Environment: Radiological Quantities and Sampling Designs. Radiation Protection Dosimetry, Vol. 92, Nos
1-3, pp. 55-57. Nuclear Technology Publishing.
Bunzl, K., G. Desmet, P. Dixon, E.M. Scott, S. Sheppard, G. Voigt, and W. Whicker. 1999. Meeting Review Some perspectives on sampling of radionuclides in the environment: report on a workshop held on ‘Sampling
Radionuclides in the Environment.’ Journal of Environmental Radioactivity, 43: 89-95.
Bird, G.A., W.J. Schwartz and M. Motycka. 1998. Fate of 60Co and 134Cs added to the hypolimnion of a Canadian
Shield lake: accumulation in biota. Can. J. Fish. Aquat. Sci., 55: 987-998.
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Bird, G.A., J.C. Tait and W.J. Schwartz. 1997. Radiological and chemical toxicity of used CANDU fuel. Atomic
Energy of Canada Limited Report, TR-767, COG-96-582-I.
Bird, G.A. and W.J. Schwartz. 1997. Background chemical and radiological levels in Canadian Shield
lakes in groundwater. Atomic Energy of Canada Limited Report, TR-761, COG-96-524-I.
Sheppard, S.C. 1997. Toxicity testing using microcosms. In: Soil Ecotoxicology, Editors, J. Tarradellas, G. Bitton
and D. Rossel, Lewis Publishers, pp. 345-373.
M.I. Sheppard, M. Stephenson. 1997. Selective extraction methods for metal speciation in soils and sediments. In
R. Prost (Editor), Contaminated Soils, 3rd International Conference on the Biogeochemistry of Trace Elements,
INRA Editions, Paris, France, 1997.
Sheppard, M.I., S.R. Peterson and S.B. Russell and J.L. Hawkins. 1996. Simulation of radionuclide transport in
soils: The effects of model structure and complexity. Proceedings: International Conference on Deep
Geological Disposal of Radioactive Waste. 1996 September 16-19, pp. 4-77 to 4-87.
Sheppard, M.I. and S.R. Peterson. 1996. The CSA Soil Model: Its limitations, as illustrated by other soil models,
and the impact on doses and derived release limits. Atomic Energy of Canada Limited Technical Report, TR740, COG-96-114.
Bird, G.A. 1996. Transport of radionuclides in rivers: A review of river transport models. Atomic Energy of
Canada Technical Report, TR-697, COG-95-321.
Amiro, B. 1996. A practical use of simple footprints when measuring evapotranspiration fluxes. 22nd
Conference of Agricultural and Forest Meteorology, Atlanta, GA, January 28 - February 2, 1996. American
Meteorological Society, Boston, MA.
Amiro, B.D. and M.J. Laverock. 1996. Tree-ring growth in a chronically gamma-irradiated forest. Journal of
Environmental Radioactivity, 31: 71-85.
Bird, G.A., M. Stephenson, R. Roshon, W.J. Schwartz and M. Motycka. 1995. Fate of 60Co and 134Cs added to the
hypolimnion of a Canadian Shield lake. Canadian Journal of Fisheries and Aquatic Sciences, 52: 2276-2289.
Bird, G.A., W.J. Schwartz and D.L. Joseph. 1995. The effect of 210Pb and stable lead on the induction of menta
deformities in ChironomusTentans larvae and on their growth and survival. Environmental Toxicology and
Chemistry, 14: 2125-2130.
Stephenson, M., W.J. Schwartz, M. Motycka, J.P.M. Ross and R.R. Henschell. 1995. Regional and basin-specific
surveys for excess helium in water at the Experimental Lakes Area, northwestern Ontario, with associated data
for radon and salinity. Atomic Energy of Canada Limited, Technical Record TR-709, COG-95-441.
Simmons, G.R., P. Baumgartner, G.A. Bird, C.C. Davison, L.H. Johnson, J.A. Tamm. 1994. An approach to
criteria, design limits and monitoring in nuclear fuel waste disposal. Atomic Energy of Canada Limited,
AECL-10737, COG-94-30.
Sheppard, M.I., M. Stephenson, D.A. Thomas, J.A.K. Reid, D.H. Thibault, M. Lacroix and S. Ford. 1995.
Aquatic-terrestrial partitioning of deep groundwater discharge using measured helium fluxes.
Environmental Science & Technology, 29: 1713-1721.
Sheppard, S.C. 1995. A model to predict concentration enrichment of contaminants on soil adhering to plants and
skin. Environmental Geochemistry and Health, 17: 13-20.
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Sheppard, M.I., D.H. Thibault, G.M. Milton, J.A.K. Reid, P.A. Smith and K. Stevens. 1995. Characterization of a
suspected terrestrial deep groundwater discharge area on the Canadian Precambrian Shield. Journal of
Contaminant Hydrology, 18: 59-84.
Amiro, B.D. 1994. Response of boreal forest tree canopy cover to chronic gamma irradiation. Journal of
Environmental Radioactivity, 24: 181-197.
Sheppard, S.C. and W.G. Evenden . 1994. Contaminant enrichment and properties of soil adhering to skin.
Journal of Environmental Quality, 23: 604-613.
Stephenson, M., W.J. Schwartz, T.W. Melnyk and M. Motycka. 1994. Measurement of advective water velocity
in lake sediment using natural helium gradients. Journal of Hydrology, 154: 63-84.
Sheppard, S.C. and W.G. Evenden. 1994. Simple whole-soil bioassay based on microarthropods. Bulletin of
Environmental Contamination and Toxicology, 52: 95-101.
Gascoyne, M. and M.I. Sheppard. 1993. Evidence of terrestrial discharge of deep groundwater on the Canadian
shield from helium in soil gases. Environmental Science and Technology, 27: 2420-2426.
Stephenson, M., W.J. Schwartz, L.D. Evenden and G.A. Bird. 1993. Identification of deep groundwater
discharge areas in the Boggy Creek catchment, southeastern Manitoba, using excess aqueous helium.
Canadian Journal Earth Science, 29: 2640-2652.
Stephenson, M., W.J. Schwartz and M. Motycka. 1993. Regional survey for He anomalies in Canadian shield
lakes: sources of variation and implications for nuclear fuel waste management. Applied Geochemistry,
8: 373-382.
Bird, G.A., W.J. Schwartz, M. Stephenson. 1993. A safe, simple method to add radionuclides to a lake. Atomic
Energy of Canada Limited, Technical Record TR-607, COG-93-170.
Gascoyne, M., J.J. Hawton, R.L. Watson, M.I. Sheppard. 1993. The helium anomaly in soil gases at the Boggy
Creek site, Lac du Bonnet, Manitoba. Atomic Energy of Canada Limited, Technical Record TR-583,
COG-92-376.
Sheppard, S.C. and W.G. Evenden. 1992. Concentration enrichment of sparingly soluble contaminants (U, Th
and Pb) by erosion and by soil adhesion to plants and skin. Environmental Geochemistry and Health,
14(4): 121-131.
Ecological Effects Assessment and Non-Human Biota
The papers in this group deal specifically with the assessment of effects on non-human
biota, or on other aspects of the environment.
Sheppard, S.C. 2002. Representative biota for ecological effects assessment of the deep geological repository
concept. Nuclear Waste Management, Ontario Power Generation. Report No. 06819-REP-01200-10089, pp. 138.
Bird, G.A., P.A. Thompson, C.R. Macdonald and S.C. Sheppard. 2002. Ecological risk assessment approach for
the regulatory assessment of the effects of radionuclides released from nuclear facilities. IAEA Third
International Symposium on the Protection of the Environment from Ionising Radiation, Darwin, Australia, July
22-26.
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Whicker, F.W., K. Bunzl, P. Dixon, M. Scott, S. Sheppard and A. Voigt. 2001 Quantities, units and terms in
radioecology. Journal of the ICRU, 1(2): 48 pp.
Sheppard, S.C. 1999. Soil microbial bioassays: quick and relevant but are they useful? Human and Ecological
Risk Assessment, 5: 697-705.
Sheppard, S. C. and W. G. Evenden. 1998. An approach to defining a control or diluent soil for ecotoxicity assays,
In: “Environmental Toxicology and Risk Assessment: Seventh Volume, ASTM STP 1333”, E. E. Little, A. J.
DeLonay, and B. M. Greenberg, Eds., Pages 215-226, American Society for Testing and Materials.
Macdonald, C.R., M.J. Laverock and L.L Ewing. 1997. Summary report of radionuclides and metals in selected
wildlife in Canada. Atomic Energy of Canada Limited Report, TR-785, COG-97-265-I.
Amiro, B.D. 1997. Radiological dose conversion factors for generic non-human biota used for screening potential
ecological impacts. Journal of Environmental Radioactivity, 35: 37-51.
Macdonald, C.R. and M.J. Laverock. 1997. Radiation exposure and dose to small mammals in radon-rich soils.
Atomic Energy of Canada Limited Report, TR-764, COG-96-550-I.
Zach, R. and B.D. Amiro. 1996. Dose prediction for plants and animals - Nuclear fuel waste management.
Proceedings of the CNS/CRPA Symposium on Non-human Biota. Ottawa, December 1-2, 1996.
Zach, R. and B.D. Amiro. 1996. Development and application of an environmental assessment methodology.
Proceedings of the International Symposium on Ionization Radiation. Stockholm, May 20-24, 1996.
Ewing, L.L., C.R. Macdonald and B.D. Amiro. 1996. Radionuclide transfer and radiosensitivity in
amphibians and reptiles. Atomic Energy of Canada Limited Report, TR-731, COG-96-06.
Macdonald, C.R., L.L. Ewing, B.T. Elkin and A.M. Wiewel. 1996. Regional variation in radionuclide
concentrations and radiation dose in caribou (Rangifer tarandus) in the Canadian Arctic; 1992-94.
The Science of the Total Environment, 182: 53-73.
Amiro, B.D. and S.C. Sheppard. 1994. Effects of ionizing radiation on the boreal forest: Canada's FIG
experiment, with implications for radionuclides. Science of the Total Environment, 157: 371-382.
Zach, R., J.L. Hawkins and S.C. Sheppard. 1993. Effects of ionizing radiation on breeding swallows at
current radiation protection standards. Environmental Toxicology and Chemistry, 12: 779-786.
Amiro, B.D. 1993. Protection of the environment from nuclear fuel waste radionuclides: a framework
using environmental increments. The Science of the Total Environment, 128: 157-189.
Sheppard, S.C., W.G. Evenden and A.J. Anderson. 1992. Multiple assays of uranium toxicity in soil.
Environmental Toxicology and Water Quality: An International Journal, 7: 275-294.
Sheppard, S.C. and W.G. Evenden. 1992. Bioavailability indices for uranium: Effect of concentration in
eleven soils. Archives of Environmental Contamination and Toxicology, 23: 117-124.
Sheppard S.C., J.E. Guthrie and D.H. Thibault. 1992. Germination of seeds from an irradiated forest:
Implications for waste disposal. Ecotoxicology and Environmental Safety, 23: 320-327.
Amiro, B.D. 1992. Baseline Concentrations of Nuclear Fuel Waste Nuclides in the Environment. AECL-10454;
COG-91-231.
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Improvements to Risk Assessment Approaches With Respect to the Biosphere
These papers deal with improvements to risk assessment models, from discussion of
underlying concepts through to descriptions of new model components
Sheppard, S.C. 2003. Technical note - An index of radioecology, what has been important? Journal of
Environmental Radioactivity, 68: 1-10.
Sheppard, S.C. 2001. Toxicants in the environment: bringing radioecology and ecotoxicology together. Invited
paper, In: Radioactive Pollutants Impact on the Environment". F. Brechignac and B.J. Howard, Eds., pages 6374, Institut de Protection et de Surete Nucleaire Collection, EDP Sciences, Les Ulis, France.
Sheppard, S.C., M.H. Klukas, and S-R Peterson. 2000. Two Dose-Estimation Models CSA-N288.1 and Nureg
1.109, 1.113 - Compared for Chronic Aquatic Releases from Nuclear Facilities. Atomic Energy of Canada
Limited Report, AECL-12066.
Butler, A.P., J. Chen, A. Aguero, O. Edlund, M. Elert, G. Kirchner, W. Raskob and M. Sheppard. 1999.
Performance assessment studies of models for water flow and radionuclide transport in vegetated soils using
lysimeter data. Journal of Environmental Radioactivity, 42: 271-288.
Elert, M., Butler, A., Chen, J., Dovlete, C., Konoplev, A., Golubenkov, A., Sheppard, M., Togowa, O., Zeevart, T.
1999. Effects of model complexity on uncertainty estimates. J. Environ. Radioact. (1998) Volume Date 1999
42 (2-3): 255-270.
Sheppard, S.C. 1998. Geophagy: who eats soil and where do possible contaminants go? J. Environ. Geol., 33:
109-114.
Bird, G.A., R.H. Hesslein, K.H. Mills, W.J. Schwartz, and M.A. Turner. 1998. Bioaccumulation of radionuclides
in fertilized Canadian Shield lake basins. The Science of the Total Environment, 218: 67-83.
Elrick, D.E., M.I. Sheppard, A. Mermoud, and T. Monnier. 1997. An analysis of surface accumulation of
previously distributed chemicals during steady-state evaporation. J. Environ. Qual., 26: 883-888.
Reid, J.A.Keith and B.J. Corbett. 1997. The effects of age-dependent dose conversion factors from ICRP-72 on
biosphere model dose predictions. Atomic Energy of Canada Limited Report, TR-776, COG-96-646-I.
Macdonald, C.R. 1997. Evaluation of the environmental protection strategies for the geological disposal of
Canada’s nuclear fuel waste and ecological risk assessment. Atomic Energy of Canada Limited Report, TR780, COG-97-152-I.
M.I. Sheppard, D.E. Elrick and S. R. Peterson. 1997. Review and performance of four models to assess the fate of
radionuclides and heavy metals in surface soil. Can. Journal of Soil Science, 77(3): 333-344.
Amiro, B.D., F.L. Johnston and L.L. Ewing. 1997. Night-time and winter measurements of atmospheric
turbulence in a Canadian shield black spruce forest. Atomic Energy of Canada Limited Technical Record,
TR-784, COG-97-249-I.
Bird, G.A., W.J. Schwartz, M. Motycka and J. Rosentreter. 1997. Behaviour of 60Co and 134Cs in a Canadian
Shield lake over five years. Atomic Energy of Canada Limited Technical Record, TR-781, COG-97-166-I.
Sheppard, S.C., L.H. Johnson, B.W. Goodwin, J.C. Tait, D.M. Wuschke and C.C. Davison. 1996. Chlorine-36 in
nuclear waste disposal - 1. Assessment results for used fuel with comparison to 129I and 14C. Waste
Management, 16 (7): 607-614.
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Ewing, L.L. and B.D. Amiro. 1996. An annotated bibliography of biosphere models for performance assessment
of nuclear fuel waste disposal. Atomic Energy of Canada Limited Report, TR-775, COG-96-636-I.
Sheppard, S.C. 1996. Discussion of the definition of critical group for post-closure assessment of nuclear fuel
waste disposal. Atomic Energy of Canada Limited Report, TR-768, COG-96-591-I.
Zhuang, Y., B.D. Amiro and L.L. Ewing. 1996. A long-term atmospheric transport model for dispersion over
meso-scale areas and implications for individual and collective doses from the disposal of Canada’s nuclear
fuel waste. Atomic Energy of Canada Limited Report, TR-760, COG-96-514-I.
Klos, R., J.A.K. Reid, P. Santucci, U. Bergström. 1996. The status of world biosphere modelling for waste
disposal assessments following BIOMOVS II. Proceedings: International Conference on Deep Geological
Disposal of Radioactive Waste. 1996 September 16-19, pp. 4-37 to 4-52.
Corbett, B.J. and J.A. Keith Reid. 1996. Detailed biosphere model calculations for iodine-129. Atomic Energy
of Canada Limited Report, TR-746, COG-96-207.
Macdonald, C.R. and M.J. Laverock. 1996. External ICRP dose conversion factors for air and water immersion,
groundshine and soil. Atomic Energy of Canada Limited Technical Report, TR-739, COG-96-106.
Zach, R., B.D. Amiro, G.A. Bird, C.R. Macdonald, M.I. Sheppard, S.C. Sheppard and J.G. Szekely. 1996. The
disposal of Canada’s nuclear fuel waste: A study of postclosure safety of in-room emplacement of used
CANDU fuel in copper containers in permeable plutonic rock Volume 4: Biosphere Model. Atomic Energy of
Canada Report, AECL-11494-4, COG-95-552-4.
Sheppard, M.I., R. Zach, S.C. Sheppard, B.D. Amiro, G.A. Bird, J.A.K. Reid and J.G. Szekely. 1996. Biosphere
model for assessing doses from nuclear waste disposal. In: Proceedings of the International High Level
Radioactive Waste Management Conference. Las Vegas, Nevada, April 29 - May 3.
Amiro, B.D. and K.W. Dormuth. 1996. A simple analysis of potential radiological exposure from geological
disposal of Canada’s nuclear fuel waste. Atomic Energy of Canada Report, AECL-11533, COG-96-13.
Sheppard, S.C. and W.G. Evenden. 1996. Retention of inorganic carbon-14 isotopic exchange in soils. Journal of
Environmental Quality, 25: 1153-1161.
Sheppard, M.I. and R. Zach. 1996. Methodology for evaluating the credibility and reliability of models for
environmental impact assessment. Atomic Energy of Canada Limited Report, TR-758, COG-96-481-I.
Reid, J.A.Keith and B.J. Corbett. 1996. Variability and uncertainty in biosphere model calculations for iodine129. Atomic Energy of Canada Limited Report, TR-759, COG-96-507-I.
Stephenson, M. and J.A.K. Reid. 1996. Technical description of a model of the carbon cycle in Canadian Shield
lakes. Atomic Energy of Canada Limited Report, TR-743, COG-96-156.
Zach, R. 1996. Nuclear fuel waste management - Biosphere Program Highlights - 1978 to 1996. Atomic Energy
of Canada Limited Report, AECL-11811.
Macdonald, C.R. 1996. Environmental radiation protection of non-human vertebrate species:
Considerations for environmental monitoring and assessment in Canada. Proceedings: International
Conference on Deep Geological Disposal of Radioactive Waste. 1996 September 16-19, pp. 4-53 to 458.
Sheppard, M.I. 1995. A biosphere model, experimental program and proposed landscape modelling approach for
radionuclide transport from a deep underground source. Applications of GIS to the modeling of non-point
source pollutants in the Vadose Zone, ASA-CSSA-SSSA Bouyoucos Conference, Mission Inn, Riverside,
California, May 1-3, 1995.
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Amiro, B.D., L.L. Ewing and J.A.K. Reid. 1995. Collective population dose estimates from aquatic dispersion for
the disposal of Canada's nuclear fuel waste. Atomic Energy of Canada Limited, Technical Record TR-708,
COG-95-436
Amiro, B.D. 1995. Some simplified radiological dose estimates using isotopic dilution in the biosphere for the
disposal of Canada's nuclear fuel waste. Atomic Energy of Canada Limited, Technical Record TR-693, COG95-286.
Amiro, B.D. 1995. Radiological dose conversion factors for generic plants and animals. Atomic Energy of
Canada Limited, Technical Record TR-658. COG-95-512.
Sheppard, S.C. and W.G. Evenden. 1995. Systematic identification of analytical indicators to measure soil load on
plants for safety assessment purposes. International Journal Analytical Chemistry, 59: 239-252.
Hawkins, J.L., M.I. Sheppard and S.S. Jorgensen. 1995. Predicting soil lead migration: how can ancient church
roofs help? Science of the Total Environment, 166: 43-53.
Reid, J.A.K., M. Stephenson, M.I. Sheppard and C.A. Milley. 1994. The wetland model for the assessment of
Canada's nuclear fuel waste disposal concept. Atomic Energy of Canada Limited, Technical Record TR-569.
COG-92-51.
Johnston F.L. and B.D. Amiro. 1994. Household humidifiers as a radiological dose pathway. Health Physics,
67(3): 276-279.
Zach, R., B.D. Amiro, P.A. Davis, S.C. Sheppard and J.G. Szekely. 1994. Biosphere model for assessing doses
from nuclear waste disposal. The Science of the Total Environment, 156: 217-234.
Amiro, B.D. and R. Zach. 1993. A method to assess environmental acceptability of releases of radionuclides
from nuclear facilities. Environment International, 19: 341-358.
Johnston, F.L. and B.D. Amiro. 1993. Radionuclide emissions from household humidifiers. Atomic Energy of
Canada Limited, Technical Record TR-576, COG-92-134.
Sheppard, M.I. and J.L. Hawkins. 1992. Church roofs and smelters: Can we model soil contaminant migration?
Ed. J.P. Vernet. Environmental Contamination - 5th International Conference - Morges, Switzerland.
Special Risk Assessment Models for 14C, 36Cl and 129I
These radionuclides are unique among HLRWM radionuclides in a number of ways.
They are relatively mobile in the environment, they are of elements that are biologically
essential, and they are of elements that are relatively abundant in the biosphere. Both
14
C, and especially 36Cl, were not initially recognized as important to HLRWM, so for
these extra research was required to develop even the basic assessment capability.
Amiro, B.D. 1996. Specific-activity relationships for calculating doses from irrigation with contaminated
groundwater. Proceedings: International Conference on Deep Geological Disposal of Radioactive
Waste. 1996 September 16-19, pp. 4-1 to 4-8.
Sheppard, S.C. 1996. Specific activity models in relation to BIOTRAC biosphere model. Atomic Energy
of Canada Limited Report, TR-745, COG-96-179.
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Sheppard, S.C., B.D. Amiro, M.I. Sheppard, M. Stephenson, R. Zach and G.A. Bird. 1994. Carbon-14 in
the biosphere: modelling and supporting research for the Canadian nuclear fuel waste management
program. Waste Management, 14: 445-456.
Updates to Parameter Values – Iodine, Chlorine, Carbon
Sheppard, M.I. and S.C. Sheppard. 2002. Solid-liquid partition coefficients, Kds: what's the value and when does
it matter? Proceedings Volume 1 of the International Congress, France, September 3-7, 2001. Radioprotection
- Colloques, 37(C1): 225-229
Bird, G.A., K.H. Mills and W.J. Schwartz. 1999. Accumulation of 60Co and 134Cs in Lake Whitefish in a
Canadian Shield lake. Water, Air and Soil Pollution, 114: 303-322.
Bird, G.A. 1997. Partition coefficients (Kd values) for Tc in shield lake sediments under oxidizing and reducing
conditions. Water Resources, 7: 1673-1678.
Sheppard, S.C. and W.G. Evenden. 1997. Variation in transfer factors for stochastic models: Soil-to-plant
transfer. Health Physics, 72(5): 727-733.
Sheppard, S.C. and B.J. Corbett. 1995. Canadian database for radionuclide transfer in the environment. Atomic
Energy Control Board Report, INFO-0542, AECB Project No. 3.151.1.
Sheppard, S.C. and W.G. Evenden. 1996. Soil-to-plant transfer of elements in natural versus agronomic settings.
Atomic Energy of Canada Limited Technical Report, TR-742, COG-96-146.
Bird, G.A. and W. Schwartz. 1996. Nuclide concentration factors for freshwater biota. Atomic Energy of
Canada Technical Report, TR-703, COG-95-397.
Macdonald, C.R. 1996. Ingestion rates and radionuclide transfer in birds and mammals on the Canadian Shield.
Atomic Energy of Canada Limited Technical Report, TR-722,
COG-95-551.
Bird, G.A. and W.G. Evenden. 1996. Transfer of 60Co, 65Zn, 95Tc, 134Cs and 238U from water to organic
sediment. Water, Air and Soil Pollution, 86: 251-261.
Sheppard, S.C. 1995. Application of the International Union of Radioecologists soil-to-plant database to
Canadian settings. Atomic Energy of Canada Limited Report, AECL-11474.
Sheppard, S.C. 1994. Parameter values to model the soil ingestion pathway. Environmental Monitoring and
Assessment, 34: 27-44.
Bird, G.A. and W.G. Evenden. 1994. Effect of sediment type, temperature and colloids on the transfer of
radionuclides from water to sediment. Journal of Environmental Radioactivity, 22: 219-242.
Amiro, B.D. 1992. Baseline concentrations of nuclear fuel waste nuclides in the environment. Atomic Energy of
Canada Limited, AECL-10454, COG-91-231.
Iodine
Sheppard, M.I., S.C. Sheppard and B. Sanipelli. 2002. Recommended biosphere model values for iodine. Ontario
Power Generation, Report No. 06819-REP-01200-10090, December 2002.
Sheppard, S.C. and M. Gascoyne. 1997. Supplement to the database of groundwater iodine, chlorine and carbon
concentrations. Ontario Hydro Report No: 06819-REP-01200-0005-R00.
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Sheppard, S.C. and M. Gascoyne. 1997. Supplement to the database of groundwater iodine, chlorine and carbon
concentrations. Ontario Hydro Report No: 06819-REP-01200-0005-R00.
Sheppard, S.C. and M. Motycka. 1997. Is the akagare phenomenon important to iodine uptake by wild rice
(Zizania aquatica)? Journal of Environmental Radioactivity, 37: 339-353.
Sheppard, S.C., W.G. Evenden and T.C. Cornwell. 1997. Depuration and uptake kinetics of I Cs, Mn, Zn and Cd
by the earthworm (lumbricus terrestris) in radiotracer-spiked litter. Environmental Toxicology and Chemistry,
16: 2106-2112.
Sheppard, S.C. 1996. Importance of chemical speciation of iodine in relation to dose estimates from 129I. Atomic
Energy of Canada Limited, Whiteshell Laboratories, Environmental Science Branch
Sheppard, S.C. 1996. Importance of chemical speciation of iodine in relation to dose estimates from 129I. Atomic
Energy of Canada Limited Report, AECL-11669, COG-96-653-I.
Bird, G.A. and W. Schwartz. 1996. Distribution coefficients, Kds, for iodide in Canadian Shield lake sediments
under oxic and anoxic conditions. Journal of Environmental Radioactivity, 35: 261-279.
Sheppard, M.I., J.L. Hawkins and P.A. Smith. 1996. Linearity of iodine sorption and sorption capacities for seven
soils. Journal of Environmental Quality, 25: 1261-1267.
Bird, G.A. and W. Schwartz. 1996. Effect of microbes on the uptake of 60Co, 85Sr, 95MTc, 131I and 134Cs by
decomposing elm leaves in aquatic microcosms. Hydrobiologia, 330: 57-62.
Amiro, B.D., S.C. Sheppard, F.L. Johnston, W.G. Evenden and D.R. Harris. 1996. Burning radionuclide question:
What happens to iodine, cesium and chlorine in biomass fires? The Science of the Total Environment, 187:
93-103.
Sheppard, M.I. and J.L. Hawkins. 1995. Iodine and microbial interactions in an organic soil. Journal of
Environmental Radioactivity, 29: 91-109.
Stephenson, M. and M. Motycka. 1995. Volatility of 125I in fresh water. Journal of Environmental Radioactivity,
28(3): 295-311.
Sheppard, M.I., D.H. Thibault, J. McMurry and P.A. Smith. 1995. Factors affecting the soil sorption of iodine.
Water, Air and Soil Pollution, 83: 51-67.
Laverock, M.J., M. Stephenson and C.R. Macdonald. 1995. Toxicity of iodine, iodide, and iodate to Daphnia
magna and rainbow trout (Oncorhynchus mykiss). Archives of Environmental Contamination and Toxicology,
29: 344-350.
Sheppard, S.C., W.G. Evenden and W.J. Schwartz. 1995. Ingested soil: Bioavailability of sorbed lead, cadmium,
cesium, iodine and mercury. Journal of Environmental Quality, 24: 498-505.
Sheppard, S.C. and W.G. Evenden. 1995. Toxicity of soil iodine to terrestrial biota, with implications for 129I.
Journal of Environmental Radioactivity, 27: 99-116.
Bird, G.A., M. Motycka, J. Rosentreter, W.J. Schwartz and P. Vilks. 1995. Behaviour of 125I added to limnocorrals
in two Canadian Shield lakes of differing trophic states. Science of the Total Environment, 166: 161-177.
Bird, G.A., W.J. Schwartz and J. Rosentreter. 1994. Evolution of 131I from freshwater and its partitioning in simple
aquatic microcosms. Science of the Total Environment, 164: 151-159.
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Amiro B.D., F.L. Johnston, S.C. Sheppard and W.G. Evenden. 1994. Emissions of iodine and cesium from
agricultural and forest burning. American Meteorological Society, 21st Conference Agricultural & Forestry
Meteorology, San Diego, CA.
Sheppard, M.I., D.H. Thibault, P.A. Smith and J.L. Hawkins. 1994. Volatilization: A soil degassing coefficient for
iodine. Journal of Environmental Radioactivity, 25: 189-203.
Sheppard, S.C., W.G. Evenden and B.D. Amiro. 1993. Investigation of the Soil-to-Plant Pathway for I, Br, Cl and
F. Journal of Environmental Radioactivity, 21: 9-32.
Sheppard, S.C. and W.G. Evenden. 1992. Response of some vegetable crops to soil-applied halides. Canadian
Journal of Soil Science, 72: 555-567.
Sheppard, M.I. and D.H. Thibault. 1992. Chemical behaviour of iodine in organic and mineral soils. Applied
Geochemistry, 7: 265-272.
Chlorine
Sheppard, S.C., Evenden W.G. and C.R. Macdonald. 1999. Variation among chlorine concentration ratios for
native and agronomic plants. J. Environ. Radioactivity, 43: 65-76.
Sheppard, M.I. and D.H. Thibault. 1997. Porous media moisture and solute (Cl and I) transport using time
domain reflectometry. Ontario Hydro Nuclear Waste Management Division Report No. 06819-REP-012000015-R00.
Johnson, L.H., B.W. Goodwin, S.C. Sheppard, J.C. Tait, D.M. Wuschke and C.C. Davison. 1995. Radiological
assessment of 36Cl in the disposal of used CANDU fuel. Atomic Energy of Canada Limited, AECL-11213,
COG-95-527.
Gascoyne, M., D.C. Kamineni and J. Fabryka-Martin. 1992. Chlorine-36 in groundwaters in the Lac du Bonnet
granite, southeastern Manitoba, Canada. Proceedings: 7th International Symposium on Water-Rock
Interaction. Edited by Y.K. Kharaka and A.S. Maest. 1992 July 13-18, pp. 931-933.
Carbon
Malley, Diane F., Cherianne McClure, Paul D. Martin, Gordon Goldsborough and Marsha Sheppard. 2003.
Determination of carbon stored per unit area in a Canadian wetland using a field-portable NIR spectrometer.
Canadian Journal of Soil Science, 82(4): 413-422.
Bird, G.A., U. Bergström, S. Nordlinder, S.L. Neal and G.M. Smith. 1999. Model simulations of the fate of 14C
added to a Canadian shield lake. Journal of Environmental Radioactivity, 42: 209-223.
Evenden, W.G., Sheppard, S.C. and Killey, R.W.D. 1998. Carbon-14 and tritium in plants of a wetland
containing contaminated groundwater. Appl. Geochem., 13: 17-21
Sheppard, S.C., Ticknor, K.V. and Evenden, W.G. 1998. Sorption of inorganic 14C on to calcite, montmorillonite
and soil. Applied Geochem., 13: 43-47.
Sheppard, S.C. and W.G. Evenden. 1996. Progressive extraction method applied to isotopic exchange of carbon14. Communication of Soil Science and Plant Analysis, 27(18-20): 3059-3071.
Sheppard, S.C. and W.G. Evenden. 1996. Retention of inorganic carbon-14 isotopic exchange in soils. Journal
of Environmental Quality, 25: 1153-1161.
Stephenson, M., W.J. Schwartz and M.F. Motycka. 1995. Fate and distribution in sediments of carbon-14 added to
Canadian Shield lakes of differing trophic state. Limnology and Oceanography, 40(4): 779-790.
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Stephenson, M., M. Motycka and W.J. Schwartz. 1994. Carbon-14 activity in the water, sediments and biota of
Lakes 226 North, 226 South and 224, Experimental Lakes Area, 1989 to 1994. Atomic Energy of Canada
Limited, Technical Record TR-634, COG-94-97.
Sheppard, M.I., L.L. Ewing and J.L. Hawkins. 1994. Soil degassing of carbon-14 dioxide: Rates and factors.
Journal of Environmental Quality, 23: 461-468.
Amiro, B.D. and L.L. Ewing. 1992. Physiological conditions and uptake of inorganic carbon-14 by plant roots.
Environmental and Experimental Botany, 32: 203-211.
Supporting Research for Biological and Biosphere Connections with the Geosphere
The connection of the geosphere and biosphere, although a very obvious and ubiquitous
natural occurrence, is difficult to model and this has not been done in a consistent way
among the many agencies interested. The transition seems to represent not only a change
in media, but more importantly a change in scientific and assessment approach. The
following publications reflect the assessment done in Canada, where the
geosphere/biosphere interface was also the bridge from a site-specific geosphere to a
generic biosphere.
Sheppard, M.I. S. Stroes-Gascoyne, J.L. Hawkins, C.J. Hamon and M. Motycka. 1997. The potential for microbial
gas production in clay-based buffer and backfill materials designed for nuclear fuel waste disposal. Paper
presentation for the 11th International Clay Conference, Ottawa, Canada, June 15-21, 1997.
Sheppard, M.I., S. Stroes-Gascoyne, M. Motycka and S.A. Haveman. 1997. The influence of the presence of
sulphate on methanogenesis in the backfill of a Canadian nuclear fuel waste disposal vault: A laboratory
study. Atomic Energy of Canada Limited Report, AECL-11764, COG-97-21-I.
Sheppard, M.I., S. Stroes-Gascoyne, J.L. Hawkins, C.J. Hamon and M. Motycka. 1996. Methane
production rates from natural organics of glacial lake clay and granitic groundwater. Atomic Energy
of Canada Report, AECL-11510, COG-95-578.
Sheppard, M.I.; Bird, G.; Clarke, D.J.; Ejeckam, R.B.; Gascoyne, M.; Hawkins, J.L.; Ladha, N.; Motycka, M.;
Sheppard, S.C.; Sikorsky, R.I.; Stevenson, D.R.; Thibault, D.H. 1997. Canadian Shield Information and
Databases and Plan for Future UFDP Siting Data Acquisition. 06819-REP-01200-047-R00
Lodha, G.S.; Brown, A.; Clarke, D.; Davison,C.C.; Ejeckam, R.B.; Gascoyne, M.; Hawkins, J.; McGregor, R.G.;
Ridgway, W.R.; Serzu, M.H.; Sheppard, M.I.; Sikorsky, R.I.; Thorne, G.A.; Tomsons, D.K.; Zach, R. 1997.
The Whiteshell Pilot Study: A Demonstration of How Existing Geotechnical Information Can Be Combined to
Characterize Areas Early in a Siting Program for a Nuclear Fuel Waste Repository. 06819-REP-01200-066R00.
Sheppard, M.I.; Hawkins, J.L.; Ridgway, W.R.; Brown, A. 1997. Inventory and Preliminary Evaluation of
Databases and Information Systems for Siting a Used Fuel Disposal Facility on the Canadian Shield.
Volume I: Main Report and Volume 2: Appendices. 06819-REP-01200-029-R00
Sheppard, M.I., J.L. Hawkins and S. Stroes-Gascoyne. 1994. Preliminary measurements of microbial gas
generation from a glacial lake clay. Atomic Energy of Canada Limited, Technical Record TR-646. COG-94328.
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Stephenson, M.; Schwartz, W.J.; Motycka, M. 1992. Regional Survey for He Anomalies in Canadian Shield
Lakes: Sources of Variation and Implications for Nuclear Fuel Waste Management. AECL-10847; COG-93-130
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APPENDIX B EXAMPLE OF DOSE ESTIMATES FOR HUMANS
VERSUS NON-HUMAN BIOTA
Purpose
In the assessment of impacts of radionuclides in the environment, there is a recent
emphasis on calculating dose to non-human biota. This is in contrast to a few years ago
when it was assumed that if humans were protected, all biota were protected. This
Appendix is an example for a present-day situation where it could be argued that there is
greater risk to non-human biota than to humans. The example is for contaminated
river-bed sediments, which is relevant to HLRWM in that the source to the biosphere of
contamination in several HLRWM disposal options would be groundwater discharge into
a surface water body.
Description of the Example
The contaminated river sediments were downstream of the outfall of a nuclear facility,
and the assessment of these has been fully documented. The suite of radionuclides found
or expected in the sediment reflected an establishment where spent fuel was handled, and
included Cs-137, Sr-90, Y-90, Co-60, Zn-65, Ru-106, Cs-134, Ce-144, Eu-154, Pb-210,
Bi-210m, Po-210, Ra-226, Rn-222, Th-232 and Am-241. The contamination was not
uniform. The mean concentration of the key contaminant, Cs-137, was 2.6 Bq kg-1 dry
weight, the highest observed concentration was 117 Bq kg-1, and the 99th percentile
concentration (which was never actually observed) was estimated to be 210 Bq kg-1. It
was observed that there were pockets of high concentrations adjacent to boulders and in
other places protected from the current. The sediments were found to support a
substantial population of clams, of several species, and these were considered to be the
non-human biota most at risk because they are long-lived, relatively sessile, and in
intimate contact with the sediment. The river is sparsely inhabited by humans, although
there are occasional visits along the shore and in boats by sport fishermen.
Exposure Assumptions
It was assumed for this Appendix that the clams may opt to inhabit the same protected
places where the contamination was especially high. Thus, they were assumed to be
perpetually exposed to the 99th percentile sediment concentration. They received
radiation exposure from both external radiation (because they absorb radiation emitted in
the sediment in which they live) and internal radiation (because they have radionuclides
in their tissues as a result of their diet and uptake from the water).
There is no present direct exposure of humans to these sediments. Concentrations in fish
tissue were observed to be very low, so that ingestion was not an important exposure
route. Clams are not harvested and consumed. There is a low probability that sediments
along the shore may become contaminated, or that someone may contact contaminated
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sediment on a boat anchor. The exposure assumption was envisioned as a sport
fisherman standing for 10 hours per year on shoreline at the average concentration of the
deep sediment. This is considered quite unlikely, and to overestimate the probable
exposure.
Dose Estimates
The dose estimates reported here are modified to fit the above exposure assumptions.
The dose to clams perpetually exposed to the 99th percentile concentration is estimated to
be 1.5 x 10-3 Gy a-1. The dose to humans exposed for 10 hours per year to the average
sediment concentration is 1.2 x 10-8 Sv a-1.
Risk Quotient
In order to compare the risks to the clam population and the human individual exposed as
described, risk quotients (RQs) were computed. The RQ is the estimated dose divided by
the guideline or threshold dose where effects may be possible. For the clam population,
the threshold is the Expected No Effect Value (ENEV) used by Environment Canada
(Bird et al. 2002) of 2 Gy a-1. For the human individual, the threshold is derived from a
risk limit and is 5 x 10-5 Sv a-1. Since Gy and Sv are comparable quantities, it is obvious
that the human threshold is 40,000-fold lower, and hence more protective.
The risk quotients are:
clam population
human individual
0.0008
0.0002
Conclusion
The risk quotient in this case was fourfold higher for the clam population than for the
human individual, although in both cases the doses are far below levels one might
consider problematic. One could argue about the exposure assumptions. However, this
is a simple and real example, where the kind of environmental contamination that might
result from a HLRWM facility could have a greater impact on non-human biota than on
humans. The reason here is simple: the non-human biota is more directly exposed
because it inhabits the most-exposed position in the environment. It is not a case of the
non-human biota being more sensitive to radiation.
References
Bird, G.A., P.A. Thompson, C.R. Macdonald and S.C. Sheppard. 2002. Ecological risk
assessment approach for the regulatory assessment of the effects of radionuclides
released from nuclear facilities. IAEA Third International Symposium on the
Protection of the Environment from Ionising Radiation, Darwin, Australia, July 2226.
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